cephadm: Get rid of injected_argv

cephadm: Get rid of injected_argv

Removed the injected_argv parameter and the injection of code in the cephadm
script we send to hosts.
Now the script is copied and after that we execute the cephadm command.
I would like to copy it only one time (when adding new hosts) but this will be
part of a future PR, together with other prs to:

- Introduce cephadm version
- Get rid of packaged/root mode
- Use pex or eggs

Signed-off-by: Juan Miguel Olmo Martínez <jolmomar@redhat.com>
Signed-off-by: Sebastian Wagner <sebastian.wagner@suse.com>