WIP: Implement VSCode prompt server

[bwateratmsft]

Along with #3364, this adds the ability for AZD to leverage VSCode to ask all of its prompts, rather than needing to know the questions on an individual basis.

[azure-sdk]

VSCode Extension Installation Instructions

1. Download the extension at https://azuresdkreleasepreview.blob.core.windows.net/azd/vscode/pr/3475/azure-dev-0.9.0-alpha.1.vsix
2. Extract the extension from the compressed file
3. In vscode a. Open "Extensions" (Ctrl+Shift+X) b. Click the ...\ menu at top of Extensions sidebar c. Click "Install from VSIX" d. Select location of downloaded file

[bwateratmsft]

It's still active for now.

[microsoft-github-policy-service[bot]]

Hi @bwateratmsft. Thank you for your contribution. Since there hasn't been recent engagement, we're going to close this out. Feel free to respond with a comment containing "/reopen" if you'd like to continue working on these changes. Please be sure to use the command to reopen or remove the "no-recent-activity" label; otherwise, this is likely to be closed again with the next cleanup pass.