Add an exposed filter to the Taxonomy overview view page

Problem/Motivation

The taxonomy overview page could become huge, with many pages, so it would be handy to have a filter to let the editor find terms

Steps to reproduce

• Install Drupal 11.x using the standard profile
• Install devel module and enable devel generate. Generate a vocabulary and terms in a hierarchy.
• For example, run drush devel-generate:terms --bundles=tags 100

Proposed resolution

1. Add a filter to the taxonomy overview page view.
2. The path to the view is [path to the overview page].
3. Let the user be able to filter in a way that makes it easier to find a particular term.
4. By default, the handler that renders the overview page form is : Drupal\taxonomy\Form\OverviewTerms

Remaining tasks

• [✓] - Create a first simple version of the new filter and taxonomy overview page
• [✓] - Solve the erratic behavior [of what? explanation required] when hierarchy is involved
• [✓] - Add test coverage

User interface changes

A new "exposed filter" is added to the taxonomy overview page, that lets the editor filter terms by an input string.

Before:

After:

Highlighted results and warning about disabled reordering:

Introduced terminology

None.

API changes

None.

Data model changes

None.

Release notes snippet

None.