Add built-in support for timeout

[josegonzalez]

It would be great to add built-in support for the options from timeout. Specifically, it would be great to be able to do something like:

cronitor --timeout-secs 600 --kill-after-secs 30 --signal HUP some/command/here

Here is the full help output for timeout on my osx system:

% timeout --help
Usage: timeout [OPTION] DURATION COMMAND [ARG]...
  or:  timeout [OPTION]
Start COMMAND, and kill it if still running after DURATION.

Mandatory arguments to long options are mandatory for short options too.
      --preserve-status
                 exit with the same status as COMMAND, even when the
                   command times out
      --foreground
                 when not running timeout directly from a shell prompt,
                   allow COMMAND to read from the TTY and get TTY signals;
                   in this mode, children of COMMAND will not be timed out
  -k, --kill-after=DURATION
                 also send a KILL signal if COMMAND is still running
                   this long after the initial signal was sent
  -s, --signal=SIGNAL
                 specify the signal to be sent on timeout;
                   SIGNAL may be a name like 'HUP' or a number;
                   see 'kill -l' for a list of signals
  -v, --verbose  diagnose to stderr any signal sent upon timeout
      --help     display this help and exit
      --version  output version information and exit

DURATION is a floating point number with an optional suffix:
's' for seconds (the default), 'm' for minutes, 'h' for hours or 'd' for days.
A duration of 0 disables the associated timeout.

Upon timeout, send the TERM signal to COMMAND, if no other SIGNAL specified.
The TERM signal kills any process that does not block or catch that signal.
It may be necessary to use the KILL signal, since this signal can't be caught.

EXIT status:
  124  if COMMAND times out, and --preserve-status is not specified
  125  if the timeout command itself fails
  126  if COMMAND is found but cannot be invoked
  127  if COMMAND cannot be found
  137  if COMMAND (or timeout itself) is sent the KILL (9) signal (128+9)
  -    the exit status of COMMAND otherwise

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/timeout>
or available locally via: info '(coreutils) timeout invocation'

My use case is cron tasks that sometimes stall (maybe a bad database connection or similar) and should be marked as failed. We run the cronitor cli in environments with only bash built-ins, so the timeout binary wouldn't be available there.