Alarming improvements

This is the combined patch to fix #4820 and #4786 

This combine patch includes:

- send the last time when data was uploaded
- send the error message if data could not be uploaded, otherwise sends 'ok'
- warning if a disk partition is above 85% full
- warning if couch process are maxed out (25 or above).

@ticoann Sorry, I made too many commits, next time I will do it better