Use test view container to show spec explorer

[nehashri]

Use the new test view container feature of VSCode to show the spec explorer.

[nehashri]

should be available in nightly >= 22-5-18

[sswaroopgupta]

Expected behavior
Should not appear for a non gauge project.

Current behavior
Should appear only for gauge project.

[sswaroopgupta]

When the same test icon is used, the other application actions are also getting invoked.
E.g: Mocha Tests with empty list is displayed in a gauge project

Question
Should we use a gauge icon instead?

[nehashri]

There seems to be an issue in VS Code which makes the activity bar icons to appear irrespective of view present in the container.

Even if a separate view container with gauge icon is added, the view container for Gauge will be shown if gauge plugin is installed. The same issue will persist and needs a fix on VS Code.