* (r10s, adb, hpk) remove getAllUpdates() and add a typical replica-API that works with increasing serials. Streamline docs a bit.
* adapt ffi to new api
* documentation: updates serials may have gaps
* get_webxdc_status_updates() return updates larger than a given serial
* remove status_update_id from status-update-event; it is not needed (ui should update from the last known serial) and easily gets confused with last_serial
* unify wording to 'StatusUpdateSerial'
* remove legacy payload format, all known webxdc should be adapted
* add serial and max_serial to status updates
* avoid races when getting max_serial by avoiding two SQL calls
* update changelog
Co-authored-by: B. Petersen <r10s@b44t.com>