SOFAST watchdog process

[bbean23]

Add a new process that can restart SOFAST in the case that it crashes unexpectedly. We believe that SOFAST should be stable, but this should be available for high-availability use cases as a back up.

Requirements of the watchdog process:

• very simple to improve stability
• minimal imports
• occasionally make a request to SOFAST to check for responsiveness
• restart SOFAST when it takes more than a threshold length of seconds to respond to requests
• restart SOFAST when system memory usage reaches a threshold
• create alert files when system memory usage reaches a critical threshold for an extended period of time
• create alert files when SOFAST is taking longer to respond than expected, but not long enough to restart it
• create alert files when SOFAST is restarted withing a threshold of seconds after restarting
• customizable threshold levels determined from a settings file