Split searchindex.json and searchservice.json models and operations into separate namespaces

[heaths]

Models and operations in searchindex.json shoud go into namespaces like so (adjusted for your language):

• Azure.Search.Documents (SearchClient, SearchClientOptions)
• Azure.Search.Documents.Models

Models and operations in searchservice.json should go into namespaces like so (adjusted for your language):

• Azure.Search.Documents.Indexes (SearchIndexClient, SearchIndexerClient, FieldBulder, attributes for FieldBuilder)
• Azure.Search.Documents.Indexes.Models

[sima-zhu]

#11475