Add -h help flag

[ashanhol]

Problem:
Our wiki's out of date. We're constantly breaking deployer without backwards compatibility. Some of this is inevitable, but it'd help a lot if we had a help flag that showed our Configuration options (and required ones) at any point of running the deployer.

Solution:
Add -h flag, ideally one that hooks into Configuration.cs so it can be kept up to date whenever we make code changes.

Additional context
./deploy-cromwell-on-azure-linux -h
./deploy-cromwell-on-azure-linux --help
deploy-cromwell-on-azure-win -h
deploy-cromwell-on-azure-win --help

deploy-cromwell-on-azure* --BadConfigOption Welcome to the Cromwell on Azure Deployer! Please run deploy-cromwell-on-azure -h for a list of required and available configuration

Sister issue for TES: microsoft/ga4gh-tes#218