Engines like Pexels provide images that one would more likely expect in a
category named ``stock_images``.
By classifying engines like Pexels more precisely, we enable a more specific
handling of them, which also helps to avoid mixing them with the more general
image search on the internet. [1]
We leave these engines *enabled* by default, take them out of ``images`` and
move them into the specialization ``stock_images``.
This makes it possible, on the one hand, for the admin to configure a tab in the
UI, and on the other hand, the user can always select the group directly using
the search syntax ``!stock_images ...``.
What we need to keep in mind:
1. Technically speaking, there are no subcategories in the strict
sense. Organizationally, the *subcategories* are derived from the
`categories_as_tabs`.
2. From an admin’s perspective, `categories_as_tabs` is the tool for
structuring their content.
3. In the context of “enabled/disabled by default”: We should avoid having
the admin have to activate many individual engines when they want to
structure their content (UI tabs).
So if we leave an engine enabled by default and **move** it from `images` to a
new category, the admin only needs to add the new category to
`categories_as_tabs` to restructure their content. If the new category is also
part of the translations (see `searx/searxng.msg` in this PR), this UI structure
would also be available internationally.
[1] https://github.com/searxng/searxng/pull/6690#issuecomment-5646291679
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
