(21450) JSON responses should be UTF-8

JSON is UTF-8, therefore our responses should also be UTF-8.
Silence Jetty INFO logging during tests
Change createdb docs example to use UTF8 encoding

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #559 from kbarber/maint/createdb_utf8

Change createdb docs example to use UTF8 encoding
Use a random jetty port in test code
Extract test webserver code into helper macro
Merge pull request #555 from grimradical/charset-fix

(21450) JSON responses should be UTF-8