Postorius fixes

[danil-smirnov]

Hey @maxking

This PR is for making Postorius-only deployment better by disabling non-existent Hyperkitty archiver (and avoiding its representation as "Active" in "Settings - Archiving" menu of a list).

Also, I've found postorius settings.py file quite outdated in comparison with the one of web image. I've migrated to it everything which seemed reasonable to me.

However, I wonder should we migrate django-compressor part as well or it's Hyperkitty-specific?

[maxking]

Thanks a lot for doing this. Postorius’ image unfortunately is neglected more than other images. But it is great to have it up-to-date and have core image support Postorius’s image in a more first class way.

I have just a minor comment, but rest looks good.

[danil-smirnov]

I see @maxking but what about django-compressor part? I suspect it might be useful for postorius image as well...

[maxking]

but what about django-compressor part? I suspect it might be useful for postorius image as well.

Postorius doesn't depend on django-compressor, not yet atleast.

[danil-smirnov]

Thanks @maxking , I've also opened #439 to keep both settings.py in the same state for better maintainability.

[maxking]

Thanks, lgtm!