Make sure that ACLs propagate to before/after save hooks.

[nlutsenko]

We were mutating the argument on database create/update operations, which is erasing an ACL key, due to the difference in mongo format.
Instead - do a deepcopy of the argument to make sure nothing gets mutated in-place.

Fixes #821, where ACL was not received in hooks.

[codecov-io]

Current coverage is 91.02%

Merging #924 into master will increase coverage by +0.01% as of 949fdcb

@@            master    #924   diff @@
======================================
  Files           72      72       
  Stmts         4163    4166     +3
  Branches       862     862       
  Methods          0       0       
======================================
+ Hit           3789    3792     +3
  Partial         10      10       
  Missed         364     364       

Review entire Coverage Diff as of 949fdcb

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