GRIT as the replacement for Helm chart tag/run untagged support

We have quite a bit of feedback in Feedback issue: New Runner registration flow (gitlab#387993 - closed) echoing the same things:

1. forcing users to use UI
2. breaking existing automations
3. it's being very hard to automate creation of "dynamic" runner configurations(different tags etc...)

GRIT is meant to be a "one-shop solution" for runner fleet management automation, perhaps we can recommend users to use it instead?

• Make sure GRIT allows to set tags/run untagged and deploy runner via Helm chart
• Write tests so we don't break this functionality
• Write docs and tutorial how to replace Helm chart with GRIT
• Analyze feature parity between Helm chart and what GRIT can do, create follow-up issues for anything missing in GRIT.

Other related issues

1. Explore creating a Helm Chart to encapsulate th... (gitlab-org/charts/gitlab-runner#494 - closed)
2. Add `create` cli command (#36891 - closed)