Add length of lock to lock details

It would be great to have the length of time we were locked at low noise, in addition to the length of time we have been in a particular state. It could just count how long we've been in NOMINAL_LOW_NOISE (600) or greater, as a LHO example. It's useful to see if we are having lock losses at a particular time of lock, possibly due to some thermalization issue, PI, or something we haven't thought of yet.

Also, if this feature could make it into the json output I could add it to our lock loss spreadsheet.