Cosmos DB: Add single partition query support

[ealsur]

Cosmos DB single partition query support

This PR adds support for the Go Cosmos DB client to execute single partition (scoped to a PartitionKey) queries.

Example API usage:

pk := azcosmos.NewPartitionKeyString("newPartitionKey")

queryPager := container.NewQueryItemsPager("select * from docs c", pk, nil)
for queryPager.More() {
	queryResponse, err := queryPager.NextPage(context.Background())
	if err != nil {
		var responseErr *azcore.ResponseError
		errors.As(err, &responseErr)
		panic(responseErr)
	}

	for _, item := range queryResponse.Items {
		var itemResponseBody map[string]interface{}
		json.Unmarshal(item, &itemResponseBody)
		// consume itemResponseBody content
	}

	// If there is need to stop and paginate, extract queryResponse.ContinuationToken and stop
}

To continue a previously stopped query:

pk := azcosmos.NewPartitionKeyString("newPartitionKey")
previouslySavedToken := "<value of a previously saved continuation token>"
queryPager := container.NewQueryItemsPager("select * from docs c", pk, &QueryOptions{ContinuationToken = previouslySavedToken})
for queryPager.More() {
	queryResponse, err := queryPager.NextPage(context.Background())
	if err != nil {
		var responseErr *azcore.ResponseError
		errors.As(err, &responseErr)
		panic(responseErr)
	}

	for _, item := range queryResponse.Items {
		var itemResponseBody map[string]interface{}
		json.Unmarshal(item, &itemResponseBody)
		// consume itemResponseBody content
	}
}

API Review diff

https://apiview.dev/Assemblies/Review/2bf4306717ca4c90b69d2d5a79e3f8e6/0161e96437934dd7a0bd657e96ab2994?diffRevisionId=471bcfa777274336bb7b4bfe03c41dad&doc=False&diffOnly=True

(Not sure why some of the APIs are marked as diffs, they were just moved to a different place in the new file, the key new APIs are ContainerClient.QueryItems, QueryOptions, QueryItemResponse)

Additional changes

• CODEOWNERS updated
• Docs/examples added
• Updated to Go 1.18, including updating the Emulator tests YML to target 1.18
• Bumped dependency of azcore to 0.23.0
• Added unit tests for the new feature and unit tests on older APIs to increase test coverage
• Added emulator tests for the new feature

[jhendrixMSFT]

@JeffreyRichter do you want to look at the API diff?

[JeffreyRichter]

No, I don't think I have to. I scanned this PR quickly and picked the APIs out.