feat: support updates in lib/boards widget

[kittaakos]

Motivation

This PR is identical to #1963 but not from a fork.

Moved from #1963 (comment):

Motivation

To enhance the libraries and the boards management.

Restore view state:

1963__restore_state.mp4
Show updates count on the side-bar:

1963__updates_count.mp4
New filter UX:

Hover for libraries and platforms:

1963__hover.mp4

Change description

• can show a badge with updates count,
• better hover for libraries and platforms,
• save/restore widget state (Closes Restore filter in library and boards manager view between app stop/start #1398),
• fixed sentence and paragraph order (Ref Reduced visual clutter in Library Manager List #1611)

Other information

• Thanks for the excellent work for @msujew's hover service in Theia. I have shamelessly copied his work as-is from the Theia repository. I wanted to exclude a Theia version update in this PR.
• Thanks for the input for @nmzaheer spotting the incorrect library paragraph and sentence order months ago in his PR.

Change description

Other information

Reviewer checklist

• PR addresses a single concern.
• The PR has no duplicates (please search among the Pull Requests before creating one)
• PR title and description are properly filled.
• Docs have been added / updated (for bug fixes / features)

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