This shall help to standardize the way how to run kas inside a docker
container on a kas file that is locally available. The pattern is
- checkout repo with kas file(s)
- go to directory where the build output should go into
- call "kas-docker build /path/to/kas.yml"
As building Isar images both require a specific docker image (that
could be changed, though) as well as additional privileges (that needs
to be changed in Isar one day), the option "--isar" selects that mode.
And because the output of an Isar build generally contains root-owned
files, the clean command is added which use docker privileges to clean
the build folder, avoiding a "sudo".
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>