Disable caching during maintained field rebuild

[hepcat72]

Summary Change Description

Disable caching during maintained field rebuild. Also clears all cache after a rebuild.

I used this branch to fix stale maintained fields on dev in 4 minutes. Before this change, the script ran all day and everything rolled back when my GlobalProtect session went stale. The maintained field values had somehow gotten cleared out when we were mucking with the database manually a few days ago, and this fixed them all (6,310 field values).

Affected Issues/Pull Requests

• Indirectly related to #985 - makes rebuild_maintained_field multiple orders of magnitude faster, with the side-effect of deleting all cached values

Review Notes

See comments in-line.

Checklist

This pull request will be merged once the following requirements are met. The author and/or reviewers should uncheck any unmet requirements:

• Review requirements
  • Minimum approvals: 1
  • No changes requested
  • All blocking issues resolved by reviewers
  • Specific reviewers: @add_username_here
  • Review period: 2 days
• Associated issue/pull request requirements:
  • [x] All requirements in affected issues marked "resolved" are satisfied
  • [x] All required pull requests are merged (or none)
• Basic requirements
  • [x] All linters pass
  • [x] All tests pass
  • [x] All conflicts resolved
• Overhead requirements
  • [x] New/changed method tests implemented/updated (or no change)
  • [ ] Updated Unreleased section of changelog.md (or no change)
  • [x] Migrations created & committed (or no change)