Update Kubernetes Resource Limits

What does this MR do?

Added Kubernetes resource limits to gitlab-pages, gitlab-shell, and KAS. Added documentation to gitlab-pages, gitlab-shell, KAS, mailroom, toolbox, and registry for resource limits.

Related issues

Relates to issue

Author checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion.

Required

• Merge Request Title and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• When ready for review, follow the instructions in the "Reviewer Roulette" section of the Danger Bot MR comment, as per the Distribution experimental MR workflow

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Not needed, added resource limits as comments and updated documentation, should not affect any tests.
• Documentation created/updated
• Added Docs for limits in necessary locations
• Tests added/updated
• Not needed, added resource limits as comments and updated documentation, should not affect any tests.
• Integration tests added to GitLab QA
• Not needed, added resource limits as comments and updated documentation, should not affect any tests.
• Equivalent MR/issue for omnibus-gitlab opened
• Not relevant to omnibus deployment.
• Equivalent MR/issue for Gitlab Operator project opened (see Operator documentation on impact of Charts changes) -Changes made will not affect the operator, commented out.
• Validate potential values for new configuration settings. Formats such as integer 10, duration 10s, URI scheme://user:passwd@host:port may require quotation or other special handling when rendered in a template and written to a configuration file

typefeature Community contribution QA:verified groupdistribution

@deriamis @WarheadsSE