nmstatectl apply merges current route state config with desired state.
Adding state: absent to route config for the interface will clear routes
before adding the desired state instead of merge. Therefore keeping only
the routes configured through the profiles.

- add a default absent rule to clear route rules entries for the table.
  nmstate by default will merge rules therefore won't clear if there are any
  old rules already present. This will make sure only rules defined by profile is present.

- mimic bootproto settings to default to static, to match network.pm.
- refactored the conditions for setting config based on bootproto.
- support to configure dhcp interface.
- fixed the way bonded interface is recognised
- add advance testing for nmstate interface config