Fact: uptime_seconds
Purpose: Return just the number of seconds of uptime.
Resolution:
Acquires the uptime in seconds via the 'seconds' key of the system_uptime fact, which uses the `facter/util/uptime.rb` module to try a variety of methods to acquire the uptime on Unix. On Windows, the module calculates the uptime by the `LastBootupTime` Windows management value.
Caveats: