feat(ingest/mongodb): support AWS DocumentDB for MongoDB

[TonyOuyangGit]

Amazon DocumentDB is a fully managed native JSON document database that has MongoDB compatibility and would work with Datahub MongoDB ingestion. However, from the doc Supported MongoDB Operations, $bsonsize operation is not supported by DocumentDB and this operation in ingestion code is to filter the document with max_document_size which by default is 16MB. Also, as far as I know from research, there's no simple way to implement an operation that can achieve what $bsonsize would do in aggregation.

In order to support the ingestion of DocumentDB, we introduced a new config hostingEnvironment and omitted the $bsonsize operation if the ingestion is for DocumentDB, this will ignore the config max_document_size and ingest documents with the default maximum 16MB.

Checklist

• The PR conforms to DataHub's Contributing Guideline (particularly Commit Message Format)
• Links to related issues (if applicable)
• Tests for the changes have been added/updated (if applicable)
• Docs related to the changes have been added/updated (if applicable). If a new feature has been added a Usage Guide has been added for the same.
• For any breaking change/potential downtime/deprecation/big changes an entry has been made in Updating DataHub

[hsheth2]

LGTM