Geo: Support --force mode (proceed even when checks fail)

Problem to solve

Preflight checks prevent accidental promotion without having done all necessary checks. This is specifically relevant for a planned failover, where a systems administrator has time to do this. In case of an actual disaster, not all preflight checks may succeed but promotion may still be required. This can result in data loss etc.

Proposal

• Implement a force mode that will allow a systems administrator to proceed even when preflight checks fail
• This should not be automatic! It will still require affirmation

Mock up:

sudo gitlab-ctl promote-to-primary-node --force

Running preflight checks...
Check A - Success
Check B - Failed
Warning: This failed check X
Check C - Failed

WARNING: Preflight checks failed but you are running this in force mode. If proceeding data loss, bad things etc may happen. This may be desired in case of an actual disaster.
Are you sure? (YES I AM SURE/NO)