Add Girder API configuration to Git Client setup scripts

[thewtex]

Set up with git config, a configuration variable that contains the user's Girder API Key. This is called with a script added to ./Utilities/GitSetup and invoked by ./Utilities/SetupForDevelopment.sh.

This variable is used, if available, for authentication to https://data.kitware.com by the Utilites/UploadBinaryData.sh script. This will help expedite testing data uploads.

CC: @blowekamp