title: keep or merge git hooks in template folder
body: <p>in a large multi-team envrionment, some teams have created some standard and some non-standard hooks.  </p>
  
  <p>git config --global init.templatedir "namedfolder" will set the hooks in "namedfolder" for all instances of git.  </p>
  
  <p>if there are pre-existing hooks, they get overwritten.  </p>
  
  <p>is there a warning that can be executed, or a way to intelligently merge the hooks?  for example, if a pre-commit hook used by one team exists that warns of staleness and the hooks are updated such that pre-commit now performs some other function that could be complimentary (or not) with the staleness check, running the above command deletes the staleness check hook.  suppose we want to append to the hooks.  not seeing a way/flag to do so unless performed separately prior to the execution of the --global above.</p>