VS code extension configuration to disable welcome-to-sourcery.py

[ryanmerolle]

Checklist

• This is a new feature, not a refactoring suggestion
• I have checked for this feature in the Sourcery documentation
• I have checked there are no open requests referencing the same feature

Description

VS code extension configuration to disable welcome-to-sourcery.py

If you use devcontainers or codespaces, this pops up every time you have the container auto install the vscode extension for sourcery.