Extract common logic out of the build operation

[ipetrov117]

This PR moves all the configuration logic, that was previously defined in the build operation, under a new package called config.

This is done, to increase testability and reusability of the code and is actually the first step needed in making the customize command work with the configuration directory.

Notable changes to the code:

1. A configuration manager has been introduced - it will handle the configurations of all the different components that have been defined in a configuration directory.
2. Parsing logic has been moved out of action/build.go and into a new config.Parse() function.
3. The Builder now directly works with the configuration manager and no longer handles the configuration part.
4. All configuration logic (e.g. kubernetes, helm, etc.) is now directly working with the new image.Configuration as opposed to shipping the full image.Definition without actually needing it.

This PR is ready for review, but will stay in "Draft", as it needs to rebase and include the changes coming from the following PRs:

• Adding optional recovery partition management #231
• Introduce crypto policy to installation options #226
• Dynamically reload kernel modules #219
• k8s init node #236
• Install RKE2 SELinux module on firstboot #230

It makes more sense to rebase the changes here, as it will be more destructive if this PR needs to be rebased onto the aforementioned ones.