Documentation/rv: Add verification/rv man pages

Add man pages for the rv command line, using the same scheme we used
in rtla.

Link: https://lkml.kernel.org/r/e841d7cfbdfc3ebdaf7cbd40278571940145d829.1668180100.git.bristot@kernel.org

Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>