Fix for extra whitespace in DnfRepositories fact entries

[bbonf]

On a clean RHEL 9.3 install, pyinfra.facts.dnf.DnfRepositores doesn't work as expected because there are extra spaces appended to dictionary keys, and prepanded to values.

That's because the parsing code splits on '=' but doesn't handle whitespace.

Also relevant for the 3.x branch

[Fizzadar]

GH seems to be confused (as usual) and is throwing a total nonsense error for this PR only despite no changes in that area.

[Fizzadar]

Thank you for fixing this @bbonf! Do you have an example repo line by any chance? Would be great to get a test added.

[bbonf]

Sure, here's an excerpt from one file:

[rhel-atomic-7-cdk-3.6-source-rpms]
name = Red Hat Container Development Kit 3.6 /(Source RPMs)

And here's another (which is parsed correctly without this change):

[epel]
name=epel

[Fizzadar]

Apologies for taking so long here @bbonf; I've cherry-picked this into v3 with a test in 2c5aa74, thank you for the fix!