misc/openhab: new v3 based upon copy from openhab2
- copy openhab2* to openhab (follow upstream)
- update to 3.0.2
- remove update script (no auto migration from v2, scrip may come back later, if needed)
- use openhab instead openhabvX directories (follow upstream)
- use openjdk 11 (new requirement)
- add UPDATING entry for users which may want to switch to v3