- move get_host_mac to RtcMemory implementation
- allow hardcoding of mac address of host on client

moved TEROS10 to wolle Library, added tests that check if all libraries compile and run successfully on an ESP32 where no peripherals are connected (see TestSensorLibraries.cpp)

- move data_struct to ClientDataPackage.hpp
- move Message definition to Message.hpp
- move Message code to Message.cpp
- move global time variable to its own namespace called esptime
  - time accessible via esptime::rtc
- Message now uses ClientDataPackage instead of data_struct
- ram_caching now uses ClientDataPackage instead of data_struct
- switched from pointer definition of Message to default constructor
- move headers to hpp files where applicable
- added ArduinoJson library (does not increase space by a lot)