Expose the copy package operation through REST API

[an0rak-dev]

Requirements

All new code should be covered with tests, documentation should be updated. CI should pass.

Description of the Change

In case we don't have the possibility to use the aptly CLI on a repository, expose the aptly copy command through the REST API.

Checklist

• unit-test added (if change is algorithm)
• functional test added/updated (if change is functional)
• man page updated (if applicable)
• bash completion updated (if applicable)
• documentation updated
• author name in AUTHORS

[neolynx]

good idea !
are you working on the implementation ?