Add basic spec and instructions to build on Fedora

[hogarthj]

This adds a basic spec file and instructions on using it with mock to build an RPM on Fedora to use normal package management to install lgogdownloader

[scx]

I created RPM packages for EL (7) and Fedora (28, 29, 30).
I hope it will be useful for someone.

Repos:
https://copr.fedorainfracloud.org/coprs/scx/lgogdownloader

See also:
https://github.com/Sude-/lgogdownloader/issues/145

[grepwood]

Why is this PR sitting here for 2 years and collecting dust?

[shakeyourbunny]

Good question. Perhaps no one really cares about it?

For my part, I settled with my own build (and update) script which is distribution agnostic and also works with the Linux subsystem of Windows 10 :)

[Chewbakka-Wakka]

Useful for me as a foundation for my own spec file.
Thnx!

fyi ... https://github.com/Sude-/lgogdownloader-lists

Dunno if that is any extra use, to include in the spec.

[grepwood]

Why is this PR sitting here for 6 years and collecting dust?

[Eschguy]

This was solved in #258, no?

[Chewbakka-Wakka]

Not quite because although that merge contains an update to the readme file giving a loose description, it does not provide a spec file enabling the build.

[Eschguy]

Ah my mistake, I misread the PR title.