Change default project limit count to 100000

What does this MR do?

It changes the default project limit count from 10 to 100,000, as it makes no sense to have such a low limit by default (read issue for more context).

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/28827

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?