gschema: split org.gnome.nm-applet.eap off

In commit 50cda26a ('gschema: move "org.gnome.nm-applet.gschema.xml" from network-manager-applet to libnma'), this schema was moved over from nm-applet even though all we need is "org.gnome.nm-applet.eap".

That's rather unfortunate, because it's sort of difficult to undo without breaking some versions of nm-connection-editor.

Let's split off the part we need (org.gnome.nm-applet.eap), but keep the other half (org.gnome.nm-applet) in place for now, until we give nm-applet users a chance to upgrade to a version that has has it.

Packagers can just choose to remove the file (e.g. %ignore in RPM) and ensure their nm-applet is new enough.