Investigate support for EtherCAT

I'm currently starting to work on EtherCAT [1] [2] slave implementation and therefore the requirement to have a EtherCAT master to control and test this slave arises.

E.g. http://etherlab.org/en/ethercat/index.php provides a Linux Kernel module to implement an EtherCAT master.

There is also https://github.com/OpenEtherCATsociety which supports Linux and Windows and even has support for EtherCAT slaves.

It should be investigated, if this makes a good addition to QtSerialBus.

[1] https://www.ethercat.org/default.htm

[2] https://en.wikipedia.org/wiki/EtherCAT