More granular control over restrictions

**Is your feature request related to a problem? Please describe.**
DoltHub has been timeouting for past hour even on the simplest of merges that take seconds locally.

**Describe the solution you'd like**
It would be nice to have restrictions applied to certain groups or to certain accounts, or to at least have a list of accounts for which DoltHub can ignore restrictions.

**Describe alternatives you've considered**
Temporary globally disabling restrictions. Had to that since there's no other options. Poblem is: it is very dangerous.

**Additional context**
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