Summary

Fixes #15597
Fixes #15850

Important notice: needs a rebase from #15532 once that's merged

Occurred changes and/or fixed issues

• Update Shell API's methods usage signature to a pattern more "up-to-date" and easy to be consumed
• Integrate the Notification Center with the Shell API
• Add information for when the Shell API is available to be consumed
• Update typedoc integration to auto-generate new documentation (remove commented code so it's enabled by default)
• Remove growls from Shell API (deprecated)
• Add new System API to Shell API
• Fixes minor issues with focus trap on Shell API methods
• add unit tests for Shell API implementation

Technical notes summary

Areas or cases that should be tested

• Check if documentation looks and builds fine
• Check if all Shell API methods are working fine and display intellisense

Areas which could experience regressions

Screenshot/Video

Checklist

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