Added information about registering AAD app domains
Added information about registering AAD app domains

Added missing information about registering Azure AAD app domains
required to complete authentication from Office clients

jasonjoh/generator-office,pkskelly/generator-office,waldekmastykarz/generator-office,jasonjoh/generator-office,andrewconnell/generator-office,andrewconnell/generator-office,WrathOfZombies/generator-office,WrathOfZombies/generator-office,jasonjoh/generator-office,OfficeDev/generator-office,pkskelly/generator-office,waldekmastykarz/generator-office,WrathOfZombies/generator-office