wrote query to sum up the number of watchlist entries for an exercise id, then wrote the test and merged development into my branch

This is no longer an enum, so we cannot reliably
translate it.

This accepts data from the updated backend
(from the previous commit) but does not display
any of the new metadata yet.

This is not tested with search results, because I could
not obtain search results locally. Suggestions on the
home page work, but no results are shown in /search

refactored statistics so that they are loaded by the statistics service and then resolved the collections bug

disabled button when not logged in, allowed get request for number of likes and has liked for not logged in user