Copy the header search to the new location
What does this MR do and why?
We're splitting off New Global Search Modal MR into a couple of MRs. That MR has already UX, backend, and a first round of frontend approved though it was suggested by frontend maintainer that it would be easier to review it in smaller parts. So this is the second part where we just copy all the header search files needed for the new implementation to the super_sidebar location, renaming them and updating the paths in files. No visual changes are expected as those files are not used yet.
We're copying the header search and not reusing it (except the translations) because first of all the new implementation needs some substantial changes in the data structure as well as in the component layout and we do not want to break the header search until the new sidebar is released. When it is released, the whole header search folder will be removed.
The MR is set to Draft as it is based off the first MR in the sequence which needs to be merged first
The paths to the final state
Related to #378542 (closed)