Extend patch API to support data block modification

This change is an effort to implement ADR.

Some considerations:

• This feature is implemented as a new API. To comply with the RFC spec, API media type must be "application/json-patch+json". The new API uses the same request mapping and HTTP method as the existing bulk update API
• Support for updating data block (i.e. 'data' and 'meta' fields in Record) is added. We are also extending metadata update support for additional fields (ancestry/parents, kind)
• There is no update to storage_openapi.yaml file under /docs/api because the swagger is generated with code now.

Active work items:

• Update tutorial documentation

Note to reviewers:

• There are a lot of seemingly unrelated small unit test changes. We made those because of a change in the mockito dependency, which performs strict mock stubbing checks by default. So, we've relaxed those checks by default in the unit test classes. The mockito dependency change was made because we wanted to introduce WebMvcTest with SpringRunner for the new API. This helps us mock the http call to the new endpoint