Resolve "Productivity Analytics MVC"

What does this MR do?

Introduces new application-wide analytics page with productivty analytics metrics

FE changes introduced in this MR:

• Adds 3 column charts (main, timeBased, commitBased) to the page with the main chart acting as a filter for the remaining charts and the MR table
• Fixes styling glitches for the filter bar introduced in

Note: The scatterplot will be delivered in a separate MR.

Screenshots

Empty screen	With data

Screencast

productivity_analytics_screencast

Local testing

1.) Enable the following feature flags via rails -c

• Feature.enable(:analytics)
• Feature.enable(:productivity_analytics)

2.) Migrate DB with bin/rake db:migrate

3.) Merge several MRs for any group (for example gitlab-org)

4.) Productivity Analytics app runs on http://localhost:3001/-/analytics/productivity_analytics

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Closes #12079 (closed)

Closes #12217 (closed)