Support upsert memo

[rodrigozhou]

What changed? Adding support to upsert memo in a similar fashion as upsert search attributes.

Why? Add ability to add/update memo fields.

How did you test it? Added unit tests. Tested locally and verified the values in ES document was correct.

Potential risks No risks. This PR doesn't change any existing code, only adds new ones (minus a few minor refactors like renaming functions).

Is hotfix candidate? No.