mkarchiso: always resolve bootstrap_packages with realpath
mkarchiso: always resolve bootstrap_packages with realpath
Make sure that relative paths are correctly resolved by always using
realpath to resolve the $bootstrap_packages value.
Additionally, simplify assigning the default value to the packages
variable.
Fixes #240 (closed)
README.profile.rst: document the packages and bootstrap_packages variables
These file paths have always been configurable, but it was never documented.