Move workflows&tools out of Community Ops handbook; clean up outdated information in Community Relations handbook

Why is this change being made?

The Community Operations program and handbook is deprecated, but its workflows and tools are not. There is a lot of information spread around the community relations handbook, and often it is confusing to know whether the page content can be taken for granted. This generates inefficient back-and-forth, not knowing what's accurate.

This MR is huge but aims to extract the relevant information, while sustaining the purpose of Community Ops for helping automate the programs.

• Create /community-relations/workflows-tools/ and merge all workflows and tools into a single directory.
• Copy the relevant tool stack listing from community-ops to the workflows-tools index page
• Move Team Budgets to a separate page in workflows-tools/
• Update all URLs to community-operations in the entire handbook; add redirect URLs for workflows/ and tools/
• Remove duplicated and outdated information from the community-ops page
• Add a stub handbook page for StackOverflow (not documented yet)
• Keep the Community Programs Automation in the Community Ops handbook
• Refine workflows/tools overview in both, the main Community Relations and workflows/tools index page for faster access

Review Apps

• Community Relations: https://community-relations-workflows.about.gitlab-review.app/handbook/marketing/community-relations/

• Workflows and Tools: https://community-relations-workflows.about.gitlab-review.app/handbook/marketing/community-relations/workflows-tools/

• Team Budgets: https://community-relations-workflows.about.gitlab-review.app/handbook/marketing/community-relations/workflows-tools/team-budgets/
• Stackoverflow stub: https://community-relations-workflows.about.gitlab-review.app/handbook/marketing/community-relations/workflows-tools/stackoverflow/

Things this MR does not

• Change the issue tracker location from https://gitlab.com/gitlab-com/marketing/community-relations/community-operations/community-operations/-/issues to something else - this needs DRIs to decide what they prefer, and document in their handbooks. E.g. community response workflows. cc @sugaroverflow
• Purge the Community Ops page, as the community program automation sites live underneath and need reviews from DRIs. cc @c_hupy

Author Checklist

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
  • Copy/paste the Slack conversation to document it for later, or upload screenshots. Verify that no confidential data is added.
• Assign reviewers for this MR to the correct Directly Responsible Individual/s (DRI)
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the Maintained by section on the page being edited
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies
• If the changes affect team members, or warrant an announcement in another way, please consider posting an update in #whats-happening-at-gitlab linking to this MR
  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.

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