fixes #51

* Automated using https://github.com/myii/ssf-formula/pull/296

* Automated using https://github.com/myii/ssf-formula/pull/292

Document and test the accept rate limiting of the rich rule.

Signed-off-by: Arnaud Patard <apatard@hupstream.com>

The current rich_rule macro is supporting to set if the connection
should be accepted or rejected or dropped but doesn't support setting
rate limiting in the 'accept' case. Add code for that.

Signed-off-by: Arnaud Patard <apatard@hupstream.com>

* Semi-automated using https://github.com/myii/ssf-formula/pull/286

Close #44.

Configuration description taken from:

* https://firewalld.org/documentation/man-pages/firewalld.conf.html

* Semi-automated using https://github.com/myii/ssf-formula/pull/159

* Automated using https://github.com/myii/ssf-formula/pull/95