New Blazor projects should have a launch.json generated

[mikadumont]

Affected Branch:
Affected Build: v2.0.14-beta.g57062101b5, v0.0.504-alpha
Affected Product Language:

Steps to reproduce:

1.Boot VS Code
2. Open a Folder
3. Ctrl + Shift + P (Help -> Show All Commands)
4. .NET : New Project
5. Choose Blazor Server app
6. Give the new project a name
7. F5 (Run -> Start Debugging)

RESULT:
Build and restore occur, but nothing else.

EXPECT:
Debugger to start, browser opens, etc. Potentially, this means generation of a launch.json isn't functioning correctly.

NOTE:
Should also work with existing c# and razor projects, where the user presses F5 and "things just work".