- Bump version: 9.18.28 → 9.18.29

- Update Host/Image support matrix
Update documentation about the Host vs. Image support and
compatibility matrix with regards to the SLES target.

- Add default /etc/kiwi.yml file
Provide a comment only etc/kiwi.yml file that contains all
parameters we support so far including a short description
This Fixes #1232

- Bump version: 9.18.27 → 9.18.28

- Delete left over print statement from unit test

- Enable BLS configuration if is supported
Fedora now uses a BLS configuration by default, but this is not supported
by all distributions. So check if is supported by the grub2-mkconfig tool
and only enable the option if that's the case.
Fixes: #1248

- Bump Fedora x86 build test to Fedora30

- Bump version: 9.18.26 → 9.18.27

- Fix btrfs_root_is_snapshot
This commit makes sure the chrooted operations of over a loop device
including btrfs subvolumes and root as an snapshot include the
`/.snapshots` subvolume mount. This is necessary for certain operations
that depend on the layout, e.g. grub configuration using `grub2-mkconfig`.