VSCODE-114: Track playground loaded and saved events

[alenakhineika]

Description

• Move preparing data for Segment to the telemetry controller to be able manage files at single place.
• Send the playground saved event when a user saves a playground to disk. No properties needed.
• Send the playground loaded event when a user loads a playground from disk.
• Refactor tests to use async calls instead of multiple done() for a single test. Multiple done lead to a situation when a test can return false values because we do not know which done was called and if the assertion section was reached at all. Some tests take more than 3 seconds to finish, therefore I increased mocha timeout for controller tests. I can assume that before they were silently passing.

Interesting that for windows the same tests take much less time.

@Anemy do you have any ideas what can be a reason?

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added

Motivation and Context

• Bugfix
• New feature
• Dependency update
• Misc

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)

[Anemy]

Awesome. Looks good. Thanks for cleaning up these tests. In future we can write all tests like this then.