When moving the search and vector_search code from the enterprise repo into the community repo, we wanted to reorganize the file structure to follow norms in community, particularly having document_sources in the libpipeline target and in the mongo/db/pipeline directory. However, the dependency structure of the search library is coupled so strong right now that the entirety of the search code would need to move with the document sources.

We should modularize the search library so that the search-related document sources (document_source_list_search_indexes, document_source_search, and document_source_vector_search) can move to mongo/db/pipeline and the libpipeline target and leave behind the rest of the search library in mongo/db/query/search.