Replace simple-git with builtin Git extension API (#461)

* Replace simple-git with builtin Git API

* Fix bug when committing file

* Use workspaceUri as the source of truth

* Pass in Git/workspace details

* Notify when the workspace isn't a Git repo

* Export controlProvider functions directly

* Don't import all of git

* Update @types/vscode

* Switch error message to use stderr

package.json

@@ -18,7 +18,7 @@
         "theme": "light"
     },
     "engines": {
-        "vscode": "^1.45.1",
+        "vscode": "^1.64.0",
         "node": ">=12.20.0"
     },
     "categories": [
@@ -139,7 +139,7 @@
         "@types/mocha": "^9.0.0",
         "@types/mustache": "0.8.32",
         "@types/node": "^14.16.0",
-        "@types/vscode": "^1.45.1",
+        "@types/vscode": "~1.64.0",
         "@vscode/test-electron": "^1.6.2",
         "ajv": "^6.9.1",
         "assert": "1.4.1",
@@ -163,7 +163,6 @@
         "azure-pipelines-language-server": "0.6.7",
         "html-to-text": "^5.1.1",
         "mustache": "3.0.1",
-        "simple-git": "1.110.0",
         "uuid": "^3.3.2",
         "vscode-extension-telemetry": "^0.1.6",
         "vscode-languageclient": "^7.0.0",