udev-rules: all values can contain escaped double quotes now (#6890)

udev-rules: all values can contain escaped double quotes now (#6890)

This is primarly useful to support escaped double quotes in PROGRAM or
IMPORT{program} directives.

The only possibilty before this patch was to use an external shell script but
this seems too cumbersome for trivial logics such as

 PROGRAM=="/bin/sh -c 'FOO=\"%s{model}\"; echo ${FOO:0:4}'"

or any similar shell constructs that needs to deals with patterns including
whitespaces.

As it's the case for single quote and for directives running a program, words
within escaped double quotes will be considered as a single argument.

Fixes: #6835