Implement a validate command in modulectl

[c-pius]

Description

Implement a validate command that takes an existing module template and performs additional validation. This should not be the same input validation as for the create command (e.g., correct formats). Rather it should verify that the created and pushed components are there and links work.

E.g., verify that info.documentation, info.repository, info.icons, resources links work. Verify that the OCM references work, ...

Reasons

Module teams and neighbors could use this to verify that the built module templates actually work.

AC

• Validation command available
• Validation command documented