Limit some NovaProject actions to projectadmin

Many actons in NovaProject were originally scoped to project
members rather than project admin because of the design of Labs.
We've since then decided that this isn't a great model since it's
not what people have come to expect about how projects are managed.
This change makes these actions limited to projectadmin.

This change also unreverts commit dd2957.

Change-Id: I51fe542f101b083397cd71fd70dc01c468b8e71a