Update "removal" language to "deletion" for groups

Problem

We're attempting to better align the deletion process between groups and projects. One inconsistency is that projects are "deleted" and groups are "removed." As we align the messaging around deletion between projects and groups, we should also consider standardizing on one term, delete or remove.

Proposal

Align on "delete" and update the language in groups to match what's present in projects. Doing so would mean replacing "remove" with "delete" in the following places:

Settings > General 1	Settings > General 2	Warning modal 1	Warning modal 2	Warning modal 3	Admin modal

We should search to make sure there aren't any additional instances that need removing. Ensure the documentation is updated accordingly.

Implementation guide

• Update text to Delete group in app/views/groups/settings/_permanent_deletion.html.haml#L6
• Update text to Delete group in app/helpers/groups/settings_helper.rb#L10
• Update text to Delete group in ee/app/views/groups/settings/_immediately_remove.html.haml
• Update docs in:
  • https://docs.gitlab.com/ee/user/group/manage.html#transfer-a-group
  • https://docs.gitlab.com/ee/user/group/#remove-a-group
  • https://docs.gitlab.com/ee/user/group/#remove-a-group-immediately