ENH: Update Git client side hooks for GitHub

The hooks help migrate existing repositories configured to contribute
through Gerrit.

The setup scripts walk the user through creating an account on GitHub,
setting up SSH keys, creating a fork, configuring their fork to the
`origin` remote, and the InsightSoftwareConsortium repository as the
`upstream` remote.

The old aliases `gerrit-push`, `gerrit-merge` are removed and new
aliases for appropriate for GitHub are created, `review-push`, `pr`,
`pr-clean` are created.

New Git tips are created, pointing out the `pr` alias, `git series`, and
`hub`.

Change-Id: I752fc24db6ed3ef3cbb403a7f4fd7c75cf7d47eb

Author: thewtex

CONTRIBUTING.md

@@ -33,9 +33,9 @@ Before you begin, perform initial setup:
 This script helps configure your GitHub fork remote, Git client-side hooks,
 and useful Git aliases. The default Git remote names for your fork and
 `InsightSoftwareConsortium/ITK` are `origin` and `upstream`, respectively.
-However, other remote names can be used.  Note that ITK defines some useful
-Git aliases, such as `pullall` or `prepush`, through the
-[`SetupGitAliases.sh`] script for general Git tasks in ITK.
+However, other remote names can be used. Note that ITK defines some useful
+Git aliases, such as `review-push`, `pr`, `pr-clean`, and `prepush`, through
+the [`setup-git-aliases`] script for general Git tasks in ITK.
 
 Visit the *Pro Git: Setup* resource in [GitHelp] for further
 information on setting up your local Git environment.
@@ -274,7 +274,7 @@ branch (*warning*: you could lose commits).
 [UpdatingThirdParty]: Documentation/UpdatingThirdParty.md
 
 [`SetupForDevelopment.sh`]: https://github.com/InsightSoftwareConsortium/ITK/blob/master/Utilities/SetupForDevelopment.sh
-[`SetupGitAliases.sh`]: https://github.com/InsightSoftwareConsortium/ITK/blob/master/Utilities/DevelopmentSetupScripts/SetupGitAliases.sh
+[`setup-git-aliases`]: https://github.com/InsightSoftwareConsortium/ITK/blob/master/Utilities/GitSetup/setup-git-aliases
 
 [ITK's Discourse]: https://discourse.itk.org/