Fixed Instance Status usage

    Instance Status in Instance Service Status were inconsistently
    used in the code base.  Sometime strings were used in places of
    object. Sometimes the wrong object type was used in place of
    another.  Sometimes lower-case strings were compared to
    upper-case string
    Added comments and type hints in various classes
    to prevent further issues and to aid in troubleshooting
    Changed usage of mysql to datastore in instance and task
    functions

Partially Implements: blueprint improve-instance-status
Change-Id: I3e36d4ab879073b685a0585d02a62dfe157a5b3c
Merge "Fixed Instance Status usage"