resolve require section from imports

[dtomasi]

What issue type does this pull request address? (keep at least one, remove the others)
/kind bugfix

What does this pull request do? Which issues does it resolve? (use resolves #<issue_number> if possible)

This PR adds a special handling of the require section in loader.ResolveImports. Instead of overwriting command and plugin constraints, it appends them to the existing ones. This was not handled correctly before, as imported "libraries" overwrote the existing constraints.

It also changes the handling of constraints for devspace versios by adding the version constraints form imported files to a already existing constraint, separated by comma.
Example: >=6.0, >=6.1

Please provide a short message that should be published in the DevSpace release notes
Fixed an issue where DevSpace did not resolve command and plugin constraints from imports

What else do we need to know?

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[89luca89]

Hi @dtomasi

Thanks a lot for the PR!
Can I ask to add an e2e test for this? So we're sure we don't have regressions in the future