Support for mirror flag when syncing rpm repositories

[vonsch]

[noissue]

[vonsch]

Btw I also considered if it would be better to use --mirror/--no-mirror python click options instead of --mirror True/--mirror False, but not sure what's better.

[mdellweg]

We use --bool/--no-bool everywhere else.

[vonsch]

@mdellweg thanks for suggestion, I modified PR

[mdellweg]

@daviddavis do you think, we need a changelog here?

[daviddavis]

I don't see the harm in adding a changelog. It's good to always call out new additions.

That said, I have no objection to not having a changelog either.

[vonsch]

@mdellweg If you prefer to have changelog entry, I can easily add one. However if I understand the CHANGES/ directory layout and file naming well, I must first create some github issue and then reference it in the ```CHANGES/<issue_number>.feature, right?

[daviddavis]

You could just use this PR number (ie CHANGES/212.feature).

[vonsch]

@daviddavis ok, added

[mdellweg]

Thank you very much!