Enocean-mqtt

- add new feature to group received EnOcean messages (33)
- bug correction and proposal for full JSON support (34)
- multi-level grouping & handling of packet.learn (35)
- fix some exceptions (36)
- support % character in MQTT password (38)
- publish packet receipt date (39)
- set status bit when sending message (41)
- fix error in device selection when sending data (43)
- add float support from MQTT messages (45)
- switch to paho-mqtt v2 (46)
- fix missing argument in paho.disconnect (47)
- fix pylint warnings

- add support for VLD messages
- set fallback mqtt_keepalive to 60 s to avoid problems with mosquitto
- apply autopep and pylint checks

- allow sending RF packets based on MQTT trigger
- accept "true" and "1" for mqtt_publish_json option
- bugfix: avoid wrong RF message data in debug log
- bugfix: always assumed BS4 RORG when sending packets
- avoid error if address is missing in configuration file
- improve documentation and logging

* set default `mqtt_keepalive` to 60 to avoid upstream issue
* more robust parsing of config files
* improve debugging output