[vscode] Support ViewBadge and tree/web view badge property

[rschnekenbu]

What it does

Adds support for ViewBadge and badge for tree views and Webview views

Fixes #12020

Contributed on behalf of STMicroelectronics

How to test

This PR adds a badge to Tree based views and webviews contributed by extensions. Thus 2 extensions based on vscode samples are to be tested with this patch.

custom-view-samples-0.0.2.zip This one provides a tree view with 2 actions (change badge value and change tooltip value). The first one will ask for a new value, the second for a new tooltip.

calico-colors-0.0.13.zip This one slightly updates the webview view vscode extensions sample, to change the tooltip when the add color is triggered, and to remove the tooltip (set to undefined) when the clear colors is triggered.

To test, install the extensions and trigger the action:

• 'Test View: change badge/tooltip value' to change the badge or its tooltip on the Test View
• 'Calico Colors: Add color' to add a tooltip to the calico colors test view. The first color does not add a badge, it only shows after the second one.
• 'Calico Colors: Clear color' to set the badge to undefined, and as indicated by the doc of ViewBadge, the badge is deleted.

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

[sgraband]

Thank you @rschnekenbu! Works great and looks good to me! Just one minor nitpick:
Could you add a note to the test description that the Add Color button inside the view does not increase the badge number? I was a bit confused by this at first.

[rschnekenbu]

Thanks @sgraband ! Indeed, I forgot to mention the 'Add Color' button not increasing the badge. This will be updated in the official PR.

[rschnekenbu]

Close PR, replaced by eclipse-theia#12330