NoSQL execute query

[JasonYeMSFT]

resolves: #2206

This PR implements a query experience similar to the Mongo scapbook for Cosmos DB NoSQL databases. To use the feature, use the "Create New NoSQL Query" command or manually create a .nosql document and open it in VS Code.

Activate the database extension and then connect to a Cosmos DB NoSQL collection via the code lens.

Write a SQL-like query command in the document.

• Use the "Execute" to get query results.
• Use the "Execute with Query Metrics" to get both results and query metrics (e.g. query cost).
• Use the "Get Query Plan" to get the parsed query plan from the written command.