Add experimental agent page UI

[mawinter69]

This PR adds an experimental agent page UI

What's new?

• New experimental flag added for agent UI
• Use experimental app-bar api
• Controls to mark offline, bring back online, update offline cause and launch on every page
• Overview page with cards
• banners for offline cause
• Dialogs for disconnect, mark offline, update offline reason (also for the old UI)

TODOs:

• Use the details-bar approach to show the monitoring data in a dialog instead of a card
• fix delete agent not working in old ui
• disconnect, mark offline, update offline cause to use new agent-subpage, for later use a dialog for this
• prepare a change in kubernetes plugin that adds 2 pages via sidepanel2.jelly that are not actions

Testing done

Screenshots (UI changes only)

Before

After

Proposed changelog entries

• Add experimental agent page UI

Proposed changelog category

/label rfe,web-ui

Proposed upgrade guidelines

N/A

Submitter checklist

• The issue, if it exists, is well-described.
• The changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developers, depending on the change) and are in the imperative mood (see examples). Fill in the Proposed upgrade guidelines section only if there are breaking changes or changes that may require extra steps from users during upgrade.
• There is automated testing or an explanation as to why this change has no tests.
• New public classes, fields, and methods are annotated with @Restricted or have @since TODO Javadocs, as appropriate.
• New deprecations are annotated with @Deprecated(since = "TODO") or @Deprecated(forRemoval = true, since = "TODO"), if applicable.
• UI changes do not introduce regressions when enforcing the current default rules of Content Security Policy Plugin. In particular, new or substantially changed JavaScript is not defined inline and does not call eval to ease future introduction of Content Security Policy (CSP) directives (see documentation).
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• For new APIs and extension points, there is a link to at least one consumer.

Desired reviewers

@jenkinsci/sig-ux

Before the changes are marked as ready-for-merge:

Maintainer checklist

• There are at least two (2) approvals for the pull request and no outstanding requests for change.
• Conversations in the pull request are over, or it is explicit that a reviewer is not blocking the change.
• Changelog entries in the pull request title and/or Proposed changelog entries are accurate, human-readable, and in the imperative mood.
• Proper changelog labels are set so that the changelog can be generated automatically.
• If the change needs additional upgrade steps from users, the upgrade-guide-needed label is set and there is a Proposed upgrade guidelines section in the pull request title (see example).
• If it would make sense to backport the change to LTS, be a Bug or Improvement, and either the issue or pull request must be labeled as lts-candidate to be considered.

[janfaracik]

Thanks for this! Curious to explore if there's a way we can fit this in with the Manage Jenkins redesign/sidebar style. Would be nice to not have two clashing UIs.

[mawinter69]

Thanks for this! Curious to explore if there's a way we can fit this in with the Manage Jenkins redesign/sidebar style. Would be nice to not have two clashing UIs.

For users coming from the dashboard it would be consistent

[timja]

Maybe we can remove nodes from system configuration? That way they always come in through a consistent UI?

[mawinter69]

This in combination with the change in actions.jelly allows to not restrict the DeleteAgentAction to the new UI. It ensures that the delete is properly rendered in the sidepanel and works as expected
@janfaracik I think that can also be used for the job page

[mawinter69]

So the actions are not sorted by name but appear in the same order as they appear in the overflow menu

[github-actions]

Please take a moment and address the merge conflicts of your pull request. Thanks!