assets: add star PNG icon from KDE Nuvola
API endpoint get: return minimum of 10 rows
API endpoint get: add "noContent" mode which returns sha1 hash of content

This is used for local caching, so that a client need not to transfer the whole content
API endpoint get: don't return "icon" component of feed anymore to save transfer bandwidth
API: integrate "getall" endpoint into "get"
API endpoint get: add support for "starred" feed
add community view