calamari_util: install_package etc.: pass pkgdir

Rather than hardcoding pkgdir, require it to be passed.
Also, infer flavor from release.  Add some usage.

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

Signed-off-by: Dan Mick <dan.mick@inktank.com>
calamari_util: add some logging

Signed-off-by: Dan Mick <dan.mick@inktank.com>
calamari-agent.py: get it working

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