Initial commit of new gembird energenie pms-lan binding for code review

Hi,
this is the initial commit for the new gembir energenie pms-lan binding.
It can control the 4 sockets orf multiple pms-lan power strips connected to your network.
WIKI page wis setup instructions is included as REDME.md.

Thanks for your feedback
Hans-Jörg
the code duplication of the sendXXX methods is quite huge. Could you rather make use of the HttpUtil class? Would that help reducing the amount of code here?