[lib.sh] Split into multiple files for readability

[lib.sh] Split into multiple files for readability

lib.sh got pretty big over time, making it hard to maintain.
Since most of the functions defined now in lib.sh are only required
during build/deploy and not in state files, move them to a new file.

While at it, prepare for running build/deploy as non-root and
set a default connection string for virsh instead of using
user specific config in ~/.config/libvirt/libvirt.conf, which
caused end user experience issues in the past.

Change-Id: Id8c2a8139e4bfdb99af2b0fad73b911ffa18ebea
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>