Added MQTT Publish ability

[dWoolridge]

Hello,

I found your version of rfxcmd and thought it was the best option to add MQTT publish capabilities. I've got it working and thought I'd make it available to you through a pull request. It's completely up to you if you want to incorporate this or not.

It should work for most of the weather sensors (0x50 - 0x57). I've tested it with sensors of type 0x50 & 0x52 on a Raspberry Pi (Raspbian GNU/Linux 11 (bullseye)) with an RFXcom RFXrec433.

Changes made:

• Added MQTT config section to config.xml.sample
• rfxcmd.py: added MQTT config reads, new function "sendMQTT" called from the decode_packet function
• Changed the code in rfxcmd.py to use the outputfile in the config instead of defaulting to /var/log/output.log. I got permission errors when it defaulted to that file.

Thanks,
dwoolridge