Updating resources with PATCH

This patch enables clients to update the resources using the PATCH HTTP
method. PATCH allows partial updates on the documents, reducing network
and processing overhead. Attributes may be removed, replaced, or added
in a single request.

Closes-Bug: #1220107

Change-Id: I8187f32b86f05fda58360cd3a51f07ae43742a3a
Merge "Updating resources with PATCH"