misc.py: roles_to_remotes: actually use attrname argument

Signed-off-by: Dan Mick <dan.mick@inktank.com>
Cleanup/simplify calamari-server task.  Major themes:

- use misc routines (sudo_write_file, roles_to_remotes)
- name roles roles and remotes remotes
- separate sqlite3 package installation, and remove when done
- better docstring

Signed-off-by: Dan Mick <dan.mick@inktank.com>