Add ClientDeactivateThreshold Update Field in Project Settings

[krapie]

What this PR does / why we need it?

Add ClientDeactivateThreshold update field in project settings.

This will provide API for setting client deactivate threshold in project.

Screenshot:

Any background context you want to provide?

ClientDeactivateThreshold is newly introduced parameter for housekeeping.

By settings this parameter, user can optimize document performance by removing unnecessary activated clients, which affects garbage collection of document.

For more information, follow: https://github.com/yorkie-team/yorkie/issues/444, https://github.com/yorkie-team/yorkie/pull/454

What are the relevant tickets?

Needs to be merged after this PR: https://github.com/yorkie-team/yorkie/pull/471

Checklist

• [x] Added relevant tests or not required
• [x] Didn't break anything

[CLAassistant]

All committers have signed the CLA.