Search endpoint

GET /search/tags/?prefix=abc&limit=10 min 3 chars fetches a list of the 10 first matching tags for autocompletion returns JSON {"tags":["tagName":"atag","tagName","btag"}]}

GET /search/users/?prefix=abc&limit=10 min 3 chars same as above for users, can contain an email address returns JSON {"users":["name":"afirstname alastname","username","ausername"}]}

GET /search/tags/{tag}/?limit=10 looks up tags that are connected most frequently to this one returns JSON {"tags":["tagName":"atag","tagName","btag"}]}