Use JSON for storing service state
Store status and sequences

This allows us to know when services make transition between
states, which will be used by the monitoring scripts.
Oneline status should show 'up+maint'
The seq_id should increment when leaving 'maint'

'maint' is to be considered a 'good state' and all transitions
from a good state should increment the seq_id.
Initial support for specifying alerts
refactoring: Minor refactoring
Initial implementation of 'alerts.txt'