Add design activity views

What does this MR do?

Part of #33051 (closed)

This builds on !33449 (merged) by adding user facing elements - HAML views and event filter support.

This ensures design activity is visible on project, group and user dashboards (see screenshots)

Feature Flag

This work is enabled behind a feature flag, enabled or disabled globally. To enable this feature, in your rails console:

Feature.enable(:design_activity_events)

Screenshots

• Project Activity

• Group Activity

• User profile

• Dashboard

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability 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