Add clean command

[rdettai]

It happens that some terraform/terragrunt cache files are left behind after destroying a stack, which can impact subsequent deployments. We propose adding a ./vast-cloud init command that runs init again on all modules. It also has a --clean option that removes the files from previous inits first.

📝 Checklist

• All user-facing changes have changelog entries.
• The changes are reflected on vast.io, if necessary.
• The PR description contains instructions for the reviewer, if necessary.

🎯 Review Instructions

• init on all modules has been made possible by adding mock_outputs on every terragrunt dependency
• Try running some deploy commands, then run init or init --clean and then continue with other operations

[rdettai]

making this a draft because the outputs are broken after running clean

[rdettai]

https://github.com/tenzir/vast/actions/runs/2691982468

[dispanser]

I tested this with:

1. vast-cloud deploy
2. vast-cloud init
3. vast-cloud init --clean
4. vast destroy

Which seems to work (destroy is still in progress). The PR review instructions don't match, but otherwise everything seems to be fine. Actual usability will be determined the next time terraform enters a borked state, which won't be too long into the future I suppose.

[rdettai]

https://github.com/tenzir/vast/actions/runs/2755099823

[rdettai]

https://github.com/tenzir/vast/actions/runs/2755847330