Project request access feature can be improved

I noticed some problems with project request access feature:

1. Even if I'm a user with master role in group that owns a project, I see Request access button on project's page.
2. I can request access despite that I already has access.
3. If I withdraw request access I'm redirected to dashboard instead of to project's page I withdrawn request of access to.
4. If I withdraw request access I receive email with Access to the ... project was denied

I think all those items on the list can be considered as bugs.

/cc @DouweM