Add tooltip to search (#2758)

You can add collection filters to a dashboard and then use them in the
search bar on the index page. eg. `email:[email protected]`

However, these collection filters are not discoverable. You have to know
about them already to know how to use them.

This change introduces a tooltip which lists the available collection
filters, allowing all users to discover what is available.

The tooltip icon is `help-circle` from [Feather icons] (MIT licensed)

We use [anchor positioning] with a [polyfill] to position the [popover] by
the tooltip.

Some basic JavaScript is introduced to show/hide the popover on hover to
ensure the tooltip behaviour works as expected for a tooltip.

I've had a first pass at the design, borrowing from existing styles. But
I don't feel strongly about it if we want to go in a different direction.

[Feather icons]: https://feathericons.com
[anchor positioning]: https://developer.mozilla.org/en-US/docs/Web/CSS/position-anchor
[polyfill]: https://github.com/oddbird/css-anchor-positioning
[popover]: https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/popover

Closes #2750

Author: jared-thoughtbot

.github/workflows/codeql-analysis.yml

@@ -34,6 +34,7 @@ jobs:
           config: |
             paths-ignore:
               - 'app/assets/builds'
+              - 'app/assets/javascripts/administrate/vendor'
 
       - name: Autobuild
         uses: github/codeql-action/autobuild@v3