DBObj_Interface_JSON: add "trimmed export" mode to list export

this mode exports only the id's of links/o2m relationships to reduce traffic.
todo: actually avoid the expensive fetch-all call...
add latest tinymce
DBObj_Interface_JSON: add plainExport mode

plainExport does not export o2m/links at all, use this for high-speed queries.
DBObj: add functions and views for working with inter-object links