[Search] Internal public API audit

[tjprescott]

Conduct an internal review of the public-facing API to ensure that the docstring keywords on internal API calls are properly plumbed through to the public facing API calls.

SearchClient.search missing: session_id, scoring_statistics
SearchIndexClient.get_synonym_maps missing: select
SearchIndexClient.list_indexes missing: select
SearchIndexerDataSourceConnection missing: identity, encryption_key
SearchIndexersClient.get_data_source_connections missing: select
SearchIndexersClient.get_indexers missing: select
SearchIndexersClient.get_skillsets missing: select

[tjprescott]

Also, there are several "get_foos" operations that should in all likelihood be "list_foos".