Move ES constants into elastic_search.py

server/app/audio_tape_helper.py

server/app/constants.py

server/app/elastic_search.py

server/app/lab_book_helper.py

server/app/main.py

server/app/routers/labbooks.py

server/app/routers/modify_comment_segment.py

server/app/routers/modify_labbook.py

server/app/routers/modify_labbook_entry.py

server/app/routers/modify_labeled_segment.py

server/app/routers/modify_tape.py

server/app/routers/search.py

server/app/routers/tapes.py