Add new category to Growth Acquisition for saas free tier user limit work

Growth::Acquisition is processing a lot of changes to accommodate the changes to the free tier. These changes are sometimes hard to categorize elsewhere without potentially mis-using other categories. The changes should have their own category that also reflects the work the group is doing.

This MR adds a new category Measurement and Locking, initially owned by groupacquisition (will move to grouputilization over time). See comment !113300 (comment 1382361651)

Approvals

Merge requests with changes to stages and groups and significant changes to categories need to be created, approved, and/or merged by each of the below:

• VP of Product @david
• The Product Director relevant to the affected Section(s) cc @ofernandez2
• The Engineering Director relevant to the affected Section(s) @wayne
• Director of Product Design @vkarnes

The following people need to be on the merge request so they stay informed:

• Chief Technology Officer @joergheilig
• Vice President of Development @clefelhocz1
• Vice President of Quality @meks
• Vice President of User Experience @clenneville
• The Product Marketing Manager relevant to the stage group(s) @supadhyaya
• Director of Technical Writing @susantacker

After Approvals and Merge

• Create an issue in the triage-ops project to update GitLab Bot automation:
  • for Category change
  • for Stage or Group change
• Mention the product group Technical Writer to update the documentation metadata
• Share MR in #product, #development, and relevant #s_, #g_, and #f_ slack channels

/cc @s_awezec /cc @kniechajewicz /cc @dstull /cc @pcalder