mongo: handle inf/-inf/NaN in connector

[jgao54]

Use jsonitor library instead of default encoding/json, add custom extension to handle NaN/Inf/-Inf cases by writing them to String type. As pointed out by @ilidemi , JSON CH does not preserve NaN/Infinity/-Infinity:

SELECT CAST('{"a": "NaN"}' AS JSON(a Float))
SETTINGS enable_json_type=1; // returns {"a": null}

I end up using the default ConfigCompatibleWithStandardLibrary because ConfigFastest results in precision loss -- we could consider enabling it as an option in the future for perf-sensitive users.

Test:

• add unit tests and e2e tests
• ran flow locally

[jgao54]

I changed this to bson.D so cdc's document type is consistent with initial load, otherwise I have to implement redundant logic for map[string]any datatype in the BsonExtension implementation.

Also realized that bson decoding libary can deserialize to either bson.D or bson.M.

Not sure if there's a huge difference in performance between the two (given bson.D is ordered), we can change this to bson.M later if it's faster.