883003 - SystemGroup validation

Add a validation to respect integer limits in PostgreSQL
Condition cleanup

More readable version without negative form.
869581 - Product without repo cannot be promoted

It makes no sense promote product without any repository. CLI will print
error message and return error code for such products.
Small fix for invalid locale input

Forged HTTP header could cause exception, nothing serious though.
Also added more defensive checking to UI parse_locale
Merge pull request #1559 from ares/bug/883003-system_groups_validation

Bug/883003 system groups validation
Merge pull request #1561 from ares/bug/869581-product_with_no_repository_promotion

869581 - Product without repo cannot be promoted
Merge pull request #1579 from ares/feature/better_locale_parsing

Small fix for invalid locale input