[5.0] Smart Search: Allow to select which taxonomies to index

[Hackwar]

Pull Request for Issue #26233.

Summary of Changes

This allows you to set which taxonomies should be indexed by a finder plugin.

Testing Instructions

1. Setup a site with some content.
2. Disable all finder plugins except for one (to test them one by one)
3. Edit the last active finder plugin and select which taxonomies to index from the list of checkboxes.
4. Run the indexer

Actual result BEFORE applying this Pull Request

All taxonomies were indexed each time.

Expected result AFTER applying this Pull Request

Only the selected taxonomies are indexed.

[richard67]

RTC

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[laoneo]

Thank you for your contribution, unfortunately the 4.4-dev branch doesn't get new features. When #40181 is merged this pr should be rebased to 5.0-dev. Thanks for understanding.

[HLeithner]

How would this look like for custom fields (in the future)? Would we add this option as custom field attribute?

[Hackwar]

#38650 adds options to set if a custom field should be indexed as text or taxonomy or none.

[richard67]

Why closed? Should we reopen the original issue?

[HLeithner]

thanks

[HLeithner]

We need documentation for this