Overhaul option and package list handling:
1.) Add missing modules "mod_proxy_scgi.so" and "mod_reqtimeout.so"
    if the package is built with shared modules enabled.
    This fixes PR pkg/43229 by Ryo HAYASAKA.
2.) Get rid of "PLIST.worker" and use "PLIST_VARS" instead.
3.) Use an option group instead of the "APACHE_MPM" configuration variable
    to configure the worker model.
4.) Enable the "apache-shared-modules" options by default. This provides
    more flexibility and matches the behaviour of a lot of other
    platforms e.g. Solaris or Linux distributions like Ubuntu.

Bump the package revision as the binary package will change by default.

(tron)