Remove use of deprecated default rec rule settings

from MythWeb.  These values should all be set from the recording rule
templates.  Fixes #11138.  Refs #11512.
Use Default recording rule template in MythWeb

when creating new recording rules.  This patch only uses values from the
Default recording rule template, but it's still better/more capable than
the old approach that pulled values for a few parameters from settings.

Patch by Paul Gardiner (thanks!) with minor changes by me.
Fixes #11512.

Signed-off-by: Michael T. Dean <mdean@mythtv.org>