Resolve "Add new "Overview" tab on user profile page"

What does this MR do?

Adds a new "Overview" tab to user profile page which displays the following 3 sections:

• a 6 months contribution graph variant
• an initial activity feed variant that shows first 5 entries max on high viewports
• an initial project list that shows first 10 entries max on high viewports

EE port: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7783

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/49801

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides

Closes #49801 (closed)