[Dev Environments] Add ability to create a Dev Environment

[bbonaby]

Suggested new feature or improvement

Currently we only support management and configuration of a Dev Environment. This now adds the capability to create an environment in Dev Home.

Scenario

1. Users can go into the machine configuration page in Dev Home and select a "Create Environment" option that will take them through the creation flow.
2. Users can go to the Environments tool page and see the progress of their environment being created.

Additional details

The work includes:

1. Adding the creation capability to the Hyper-V extension
2. Creating the creation flow in the machine configuration tool page, that includes presenting an adaptive card UX from the extension within Dev Homes new "Create Environment" flow.
3. Creating any usable custom adaptive card renders needed to present the above UX
4. Adding UX updates to the Environments page that will show the user that an adaptive card is being created.

Tasks

• [Hyper-V Extension] Add ability for the Hyper-V extension to create VMs from the VM gallery #2442
• Add ability for Dev Home to display settings cards from an adaptive card #2488
• Add Hyper-V settings card styled adaptive cards  #2489
• Add initial environments creation flow to the machine configuration tool #2493
• Finish UI for environments creation #2539
• Add updates to allow for Dev Box creation in Dev Home #2639