add new status sub and move code from test

add new status sub and move code from test

old status sub was renamed ifquery_check

also check if local config exist or if local config is too old.
(fixme : compare mtime, maybe could we use some kind of version for this?)

we can have 4 status code:

- pending : local config is absent but sdn.cfg exist
- unknown : local config is too old, we can't be sure of the running state
- error : local config is present, but don't match the running state
- available : all is ok, local config is present and match running state.

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>