Describe the solution you'd like
A player who is not the owner of a given grave should not be able to break it unless grave robbing is enabled.

Overrides:

• Player has appropriate permission level
• Player uses a skeleton key on the grave

As the recent branch merger implements this feature I will be closing this issue.

Note: this will need some work later on, when the config has been implemented, as right now it defaults to requiring operator permission level 4 to break graves owned by others.