Support different versions per instance of a component

[simu]

This PR changes Commodore to

• Create separate worktrees for each component alias
• Create class symlinks for each component alias
• Create each alias target with only the defaults and component class symlinked from the alias worktree
• Read instance versions from parameters.components.<instance-name>

Note that per-instance versions only work correctly only for components which use ${_base_directory} in their config when specifying Jsonnet files or Helm chart/YAML locations in kapitan.compile and kapitan.dependencies. Note, that components should use ${_base_directory} anyway, and new components created from the template use ${_base_directory} out of the box.

TODO:

• [ ] Implement support for overriding the URL or path for individual component instances
• [ ] Test cases which cover new features

Resolves #563

Checklist

• [x] Keep pull requests small so they can be easily reviewed.
• [ ] Update the documentation.
• [ ] Update tests.
• [x] Categorize the PR by setting a good title and adding one of the labels: bug, enhancement, documentation, change, breaking, dependency as they show up in the changelog