frr: Update to version 8.0.1

frr: Update to version 8.0.1

- This v2 version used the frr-8.0.1 source instead of the frr-frr-8.0 source
- Update from 6.0 to 8.0.1
- 8.0.1 requires libyang for the build. Introduced with separate patch in this series.
- 6.0 is only compilable with python2.
  python3 compatability was introduced in version 7.4
- Previously confirmed that building frr-8.0 was successful with only python3 available
- Added --disable-static to the ./configure options.
- Rootfile updated
- Changelog from 6.0 to 8.0.1 is too large to include here. It can be viewed to obtain
   more details at https://github.com/FRRouting/frr/releases

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>