Fetch device type in parallel for faster startup time in plants with many devices

[orlopau]

When a new plant is created from a slice of device addresses, the type of the device must be determined.

This is achieved by scanning the SunSpec module table (via modbus). When the tables have been read, they are cached for the runtime of the application.

Scanning devices is currently performed in sequence, but can be easily parallelized, resulting in a huge startup performance gain in plants with many devices.