Add Support for TaskGroup.id and TaskGroup.isDefault

[tsmaeder]

What it does

Adds support for id and isDefault and includes a small drive-by fix in the Task implementation where the taskRunOptions object was not properly initialized.

Fixes #11519

Contributed on behalf of ST Microelectronics

How to test

1. Install the attached vscode extension. It is built from https://github.com/tsmaeder/castletest
2. Open a workspace that generates some tasks. I use the source of Theia
3. Configure some tasks, playing with the "id" and "default" fields
4. Inspect the task by invoking "Dump task info to console" from the command palette and make sure the right values are shown for "isDefault" and "id".

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[tsmaeder]

castletest-0.0.1.zip

[vince-fugnitto]

LGTM 👍 I confirmed the changes work as expected:

• confirmed that the compatibility report is now marked as supported for TaskGroup.id and TaskGroup.isDefault
• there is completion help when editing tasks to set the group (including isDefault)
• running the default "build task" works as expected
• running the default "test task" works as expected