www/tt-rss: Simplify ttrssd rc script

ttrssd rc script has a check if a local database is ready such that at
startup ttrssd will wait 10 seconds for a database connection.

With daemon you can restart the child process with a delay such that the
rc script can be simplified to use command and command_args.

PR: 279803
Author: Derek Schrock <dereks@lifeofadishwasher.com>
Reviewed-by: cy
Differential Revision: https://reviews.freebsd.org/D45618