packaging: Add Fedora packaging files

[Conan-Kudo]

This PR adds the packaging data for Fedora originating from the Fedora Dist-Git.

While the Fedora packaging in Dist-Git is the authoritative source, a copy of this in this repository will help enable spread testing.

Note the snapd package cannot be built without the patch from #3162.

[morphis]

Please drop a6a328f as we can't merge that patch. We should just add the necessary bits for packaging/fedora-* and leave everything else as is.

[Conan-Kudo]

@morphis It's dropped, but the packaging is effectively useless now, since it won't build.

[codecov-io]

Codecov Report

Merging #3366 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3366   +/-   ##
=======================================
  Coverage   77.55%   77.55%           
=======================================
  Files         366      366           
  Lines       25146    25146           
=======================================
  Hits        19501    19501           
+ Misses       3897     3896    -1     
- Partials     1748     1749    +1

Impacted Files	Coverage Δ
overlord/snapstate/snapstate.go	81.65% <0%> (-0.25%)	⬇️
overlord/ifacestate/helpers.go	62.86% <0%> (ø)	⬆️
cmd/snap/cmd_aliases.go	96% <0%> (+2%)	⬆️
interfaces/sorting.go	96.66% <0%> (+3.33%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 57eaf8f...57e766d. Read the comment docs.

[morphis]

You can use $(systemd-escape -p $SNAP_MOUNT_DIR) here

[morphis]

@morphis It's dropped, but the packaging is effectively useless now, since it won't build.

Thanks! See 67673a2 for a fix for the last patch we have in Fedora and not merged upstream yet. Actually the fixed LD script is only available in F26 so we need to fix this from the spec file to have a proper fix available for F24-F26.

[zyga]

❤️

Thank you @Conan-Kudo and @morphis for getting us here :-)

[zyga]

I'm merging this. Please iterate on subsequent changes.