ci: Use upstream submodule to build vscode

Issue: Adapt the CI pipeline to use patch files and th... (#36 - closed)

What does this MR do?

It writes new build scripts to create VSCode Fork builds based on a patch-based strategy. The new build scripts patch a git submodule of the VSCode upstream project and then run create distribution artifacts of VSCode for the Web and VSCode Server. These build scripts are heavily inspired in the existing build process of the VSCode Fork.

Previous work

• Add VSCode upstream project as a submodule of V... (#34 - closed)
• Convert commits that modify VSCode upstream int... (#35 - closed)

Demo

The following demo demonstrates that the artifact produced by the new build job contains our VSCode Fork modifications in the Web IDE. It explores the following changes:

1. willShutdown method to display a message when the user will exit the Web IDE and changes are not saved.
2. Customizations to the Welcome Screen.
3. Customizations to the Extensions Marketplace and Debug panels.

web_ide_demo_new_patch_strategy.mov

How to test?

1. The CI pipeline should pass.
2. In your local environment, run:
   1. gl-scripts/prepare-vscode-upstream.sh && gl-scripts/build-and-bundle-web.sh to build VSCode for the Web.
   2. gl-scripts/prepare-vscode-upstream.sh && gl-scripts/build-and-bundle-server.sh to build the VSCode Server.