Update Shell API's method signatures and enable typedoc integration

[aalves08]

Summary

Fixes #15597

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

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

• The PR is linked to an issue and the linked issue has a Milestone, or no issue is needed
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• The PR template has been filled out
• The PR has been self reviewed
• The PR has a reviewer assigned
• The PR has automated tests or clear instructions for manual tests and the linked issue has appropriate QA labels, or tests are not needed
• The PR has reviewed with UX and tested in light and dark mode, or there are no UX changes
• The PR has been reviewed in terms of Accessibility