feature(data-types): add data-types from https://github.com/zarr-developers/zarr-python/pull/2874

data-types/fixed-length-ascii/README.md

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+# Fixed-length ASCII data type
+
+Defines a data type for fixed-length ASCII strings.
+
+## Permitted fill values
+
+The value of the `fill_value` metadata key must be a string.
+
+## Example
+
+For example, the array metadata below specifies that the array contains fixed-length ASCII strings:
+
+```json
+{
+    "data_type": "fixed-length-ascii",
+    "fill_value": "",
+    "configuration": {
+      "length_bits": 24
+    },
+}
+```
+
+## Notes
+
+TBD
+
+## Change log
+
+No changes yet.
+
+## Current maintainers
+
+* [zarr-python core development team](https://github.com/orgs/zarr-developers/teams/python-core-devs)

data-types/fixed-length-ascii/schema.json

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+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "oneOf": [
+    {
+      "type": "object",
+      "properties": {
+        "name": {
+          "const": "fixed-length-ascii"
+        },
+        "configuration": {
+          "type": "object",
+          "properties": {
+            "length_bits": {
+              "type": "integer"
+            }
+          },
+          "required": ["length_bits"],
+          "additionalProperties": false
+        }
+      },
+      "required": ["name", "configuration"],
+      "additionalProperties": false
+    },
+    { "const": "fixed-length-ascii" }
+  ]
+}

data-types/fixed-length-bytes/README.md

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+# Fixed-length bytes data type
+
+Defines a data type for fixed-length byte strings.
+
+## Permitted fill values
+
+The value of the `fill_value` metadata key must be a string.
+
+## Example
+
+For example, the array metadata below specifies that the array contains fixed-length byte strings:
+
+```json
+{
+    "data_type": "fixed-length-bytes",
+    "fill_value": "",
+    "configuration": {
+      "length_bits": 24
+    },
+}
+```
+
+## Notes
+
+TBD
+
+## Change log
+
+No changes yet.
+
+## Current maintainers
+
+* [zarr-python core development team](https://github.com/orgs/zarr-developers/teams/python-core-devs)

data-types/fixed-length-bytes/schema.json

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+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "oneOf": [
+    {
+      "type": "object",
+      "properties": {
+        "name": {
+          "const": "fixed-length-bytes"
+        },
+        "configuration": {
+          "type": "object",
+          "properties": {
+            "length_bits": {
+              "type": "integer"
+            }
+          },
+          "required": ["length_bits"],
+          "additionalProperties": false
+        }
+      },
+      "required": ["name", "configuration"],
+      "additionalProperties": false
+    },
+    { "const": "fixed-length-bytes" }
+  ]
+}

data-types/fixed-length-utf32/README.md

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+# `fixed_length_utf32` data type
+
+This document defines a data type for fixed-length, null-terminated Unicode strings encoded using [UTF-32](https://www.unicode.org/versions/Unicode5.0.0/appC.pdf#M9.19040.HeadingAppendix.C2.Encoding.Forms.in.ISOIEC.10646). UTF-32, also known as UCS4, is an encoding of Unicode strings that allocates 4 bytes to each Unicode code point.
+
+"Fixed length" as used here means that the `fixed_length_utf32` data type is parametrized by a integral length, which sets a fixed length for every scalar belonging to that data type.
+
+"Null-terminated" as used here means that, for an integral length `L`, a `fixed_length_utf32` data type parameterized with `L` can represent a string shorter than `L` by adding null bytes to the end of that string until it has length `L`. 
+
+### Name
+
+The name of this data type is the string `"fixed_length_utf32"`
+
+### Configuration
+
+This data type requires a configuration. The configuration for this data type is a JSON object with the following fields:
+
+| field name | type | required | notes |
+|------------|----------|---|---|
+| `"length_bytes"` | integer | yes | The number MUST represent an integer divisible by 4 in the inclusive range `[0, 2147483644]` |
+
+> Note: the maximum length of 2147483644 was chosen to match the semantics of the [NumPy `"U"` data type](https://numpy.org/devdocs/reference/arrays.scalars.html#numpy.str_), which as of this writing has a maximum length in code points of 536870911, i.e. 2147483644 / 4.
+
+> Note: given a particular `fixed_length_utf32` data type, the length of an array element in Unicode code points is the value of the `length_bytes` field divided by 4.
+
+### Examples
+
+```json
+{
+  "name": "fixed_length_utf32",
+  "configuration" : {
+    "length_bytes": 4
+  }
+}
+```
+
+## Fill value representation
+
+The value of the `fill_value` metadata key must be a string. When encoded in UTF-32, the fill value MUST have a length in bytes less than or equal to the value of the `length_bytes` specified in the `configuration` of this data type.
+
+## Codec compatibility
+
+This data type is compatible with any codec that supports arrays with fixed-sized data types.
+
+## Notes
+
+This data type is designed for NumPy compatibility. UTF-32 is not a good fit for many applications that need to model arrays of strings, as real string datasets are often composed of variable-length strings. A variable-length string data type should be preferred in these cases.
+
+## Change log
+
+No changes yet.
+
+## Current maintainers
+
+* [zarr-python core development team](https://github.com/orgs/zarr-developers/teams/python-core-devs)

data-types/fixed-length-utf32/schema.json

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+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "oneOf": [
+    {
+      "type": "object",
+      "properties": {
+        "name": {
+          "const": "fixed_length_utf32"
+        },
+        "configuration": {
+          "type": "object",
+          "properties": {
+            "length_bytes": {
+              "type": "integer"
+            }
+          },
+          "required": ["length_bytes"],
+          "additionalProperties": false
+        }
+      },
+      "required": ["name", "configuration"],
+      "additionalProperties": false
+    },
+    { "const": "fixed_length_utf32" }
+  ]
+}