Loosen requirements for cascading protection: instead of requiring that both edit...

Loosen requirements for cascading protection: instead of requiring that both edit=sysop and move=sysop (and any other custom restriction types be set to sysop as well), just require edit=sysop and leave the other restriction types alone. This makes it possible to protect a page with e.g. edit=sysop and move=autoconfirmed and still use cascading protection, but only through the API: the UI won't do this (yet) because the JS greys out the cascade checkbox (that'll need to be fixed).