AVD Blueprint v1.5

Many changes, including now, everything is self-contained. Meaning that what we need is either in the \Blueprint folder, or the \Scripts folder.

• Can now purge key vault. We no long set "Purge Protection" to true
• Blueprint can be run in AzureCloud or AzureUSGovernment with very little reconfiguration needed
• Updated Win10 EVD Gallery SKU list to 21H1
• Changed DDoS Protection Plan default to 'false'
• Updated some Azure API versions for compatibility in both above-mentioned clouds
• Created a "Examples and Samples" folder, and populated that with decent sample configuration, import, and assignment files
• Extensive re-write to Readme.