better support for airgap mode 'exists', secure rke2 token by default, allow setting rke2_node_name, implement local artifact download and push to remote fallback

[simonfelding]

Description

There's a bunch of stuff in this commit. I realize it could have been multiple pull requests. Sorry about that.

• added better support for airgap mode 'exists' in rke2.yml
• deprecate rke2_snapshooter spelling error
• secure rke2 token by default
• fix indent of registries config (broke with tls_no_verify set)
• allow setting rke2_node_name as node name
• split logical and to multiple lines for readability
• made the role guess if server or agent based on group it belongs to
• implement local artifact download and push to remote fallback
• updated documentation to match

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] This change requires a documentation update
• [ ] Small minor change not affecting the Ansible Role code (GitHub Actions Workflow, Documentation etc.)

How Has This Been Tested?

reset my local cluster entirely and ran each feature against it.

[MonolithProjects]

Hi @simonfelding, please resolve the conflicts

[simonfelding]

@MonolithProjects I fixed the conflicts, is it okay now?