Run mode

[connectdotz]

This PR is mainly to implement the RunMode proposal #1058.

The goal is

1. reduce confusion (runMode="off" has greatly been misunderstood).
2. grouping UX-related settings to help improve discovery.
3. introduce a new "deferred" mode to better support large projects and not-yet-ready projects.
4. make the extension "less intrusive"

Additional changes (beyond #1058):

• replaced TestExplorer's inline menu (autoRun, coverage) with a update-runMode button. Also integrated with testing framework's runProfile configuration mechanism.
• replace the errorMessage pop-up with a less intrusive error notification mechanism: terminal error + quick-fix-chooser
• added new command to save real-time runMode to settings.json, double up as a runMode migration command.
• fix a few reveal output terminal bugs. It should be more true to "on-run" now.

Internal extension-development change:

• clean up some staled/orphan files.
• added coverage comparison script
• add orphan image script to find and remove.

Reminder

We should move "autoClearTerminal" in here as well. But decided to leave it out for now since there is another outstanding work regarding Test Results tab. We can do the setting migration then.

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resolve #1030
resolve #1025

[coveralls]

Pull Request Test Coverage Report for Build 6473103950

• 503 of 503 (100.0%) changed or added relevant lines in 19 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.01%) to 97.743%

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Totals
Change from base Build 6201822640:	-0.01%
Covered Lines:	3822
Relevant Lines:	3839

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💛 - Coveralls