Add xxxxTimes elapsed time keywords, starting with getVisit and updateTelStatus

Add keywords declaring the timings of important commands/processes. For the case of the gen2actor, start with getVisit and updateTelStatus, since the underlying calls to the Gen2 reqframes and the opdb inserts have proven to occasionally be problematically slow.

I think the actor should declare when there is a problem (and not the alerts actor), and that the timing keywords can have multiple fields. For example:

getVisitTiming=status,reqframesTime,telStatusTime
    status                  = "OK" or a non-"OK" warning string
    reqframesTime   = the elapsed time for the Gen2 reqframes call
    telStatusTime     = the elapsed time for the tel_status, etc. insert. Maybe NaN if none.

STS could alert on the status string, and allow plotting whichever fields it deems important.

I'm actually proposing this a general mechanism. Think fpsIterationTimes with a handful of major segments (cobra moves, MCS times, calculation times). Or ccdReadTimes or h4RampTimes with at least the header construction and file writing times. Group all into an STS page, maybe?