New MQTT structure and history logging

What's Changed

• General support for ESP32 boards as the GPIO can now be set in the software. So you can upload the firmware and NVRAM partition layout directly. It is also possible to upload the firmware in the GUI. As there are many configuration changes you have to go through the setup again if you update from an earlier version.
• Complete new MQTT structure supporting much more information as also device status, ...
• History support for storing the month first values
• preparation to supporting more than 1 meter
• additional metadata for easier handling in MQTT/time series databases

Full Changelog: 1.1.0...2.0.0

1.1.0

• Added "last will" topic to see On-/Offline status
• some minor optimizations

Full Changelog: 1.0.0...1.1.0

first release with everything working fine

1.0.0

README