Abstract machine class for use by juju and maas

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
Utilize base machine class

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
Re-enable api calls as current tests work

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
cosmetic changes on variable names

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
make use of tag_names property

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
add machine documentation

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>