feat: Allows promoting the charm for arm64 arch

[saltiyazan]

Description

Allows promoting the charm for arm64 arch, adds an arch selection.
Depends on #242

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that validate the behaviour of the software
• I validated that new and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have bumped the version of the library

[kayra1]

the integration tests are still not passing for some reason

[saltiyazan]

the integration tests are still not passing for some reason

They will once #242 is merged, the fix is there. I can extract it and bring it here or in a separate PR if the review there takes longer.