Add possibility to sync only the latest version of Icinga repos

[mkayontour]

The syncing of repositories should be configureable for latest versions. Maybe provide /latest path to sync from?

Could this be possible to implement?

[LordHepipud]

I will think about a solution for this. Thank you for the idea!

[LordHepipud]

We have made some cleanup on the repostiory side to remove older Icinga Agents. This should keep the size of the repository way smaller and doesn't require us to add another logic to the manager.