[FEATURE] Support multiple sketches

[haschdl]

Scenario
I organize my Processing sketches in git repositories, meaning I work with repositories in Visual Studio containing several sketches. When running the command Processing: Create Task File, the extension shows an error Create a [folder name].pde file first!.

Describe the solution you'd like
It would be more flexible and useful to have the extension work with multiple sketches per project, and make it work with other extensions such as Code Runner. This is how it works for example with Python scripts in Visual Studio.

[AvinZarlez]

After some thought about this feature, there are multiple issues that come up with implementation.

Specifically, there wouldn't be a run task anymore. You'd need to have a custom run task for each project. Which requires a much more complicated, dynamically generated task file, and a lot more extra keystrokes for set up.

Question for you @haschdl : Does opening each project in a multi root workspace just work? https://code.visualstudio.com/docs/editor/multi-root-workspaces

Rather than opening the folder of your repo with all your sketches as subfolders, if you open each folder as multi-root workspaces within VSCode in theory should make this extension and others work as you run build tasks for the appropriate sketch.

If I am wrong and that doesn't work though, let me know

[AvinZarlez]

Further note: Once you open all those workspaces, you can save a workspace file into your repo that you can open in the future with VSCode to automatically open those workspaces (aka sketches) individually