Add "vcpkg configure environment" release pipeline and subcommands.

[BillyONeal]

This adds the "vcpkg configure environment" formerly-separate-product commands to vcpkg. "vcpkg-ce", formerly "Project Cella" formerly "Project Northfield" is an incubating separate product to get vcpkg solving for all build time dependencies, including tooling, rather than only sources. Initial releases touching these commands will be in a very rough "collect feedback" state, and the commands may be changed or removed at any time. (Completely separating from the vcpkg command proper is still a possible outcome, for example)

This change incorporates many peoples' work, not only my own, and will not be squashed. In particular, but not limited to:

• @fearthecowboy 's work as the overall technical lead of the vcpkg-ce project
• @ras0219 's work to get a separately installable vcpkg workable, and the "x-forward" prototype that was Demonstrate passing through arguments with z-forward test function #243
• @vicroms 's work harmonizing manifest format(s) with the prototype
• @benmcmorran 's work showing me how to get automated creation of GitHub releases working.

The new release process if there are updates to the "configure environment" components is:

1. Update the azure-pipelines/vcpkg-ce-sha.txt to whatever is desired from microsoft/vcpkg-ce
2. git fetch origin && git push internal origin/main:main, which kicks off producing the signed builds as described here in azure-pipelines/signing.yml. This ensures that things signed by Microsoft are actually from Microsoft.
3. The push above will automatically kick off https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_build?definitionId=13610 which will create a draft release in this repo. Example: https://github.com/microsoft/vcpkg-tool/releases/tag/2021-11-18
4. If OK, publish the release created by the previous step.
5. Create a PR updating the date and relevant SHAs in microsoft/vcpkg (for example Update tool to 2021-11-15. vcpkg#21471 )

[ras0219-msft]

I forgot to post these earlier, so my apologies if they don't line up with the current files.

[ras0219-msft]

Requesting revert of the vcpkg list breaking changes before merge