Allow socket-like IPC mechanisms to transfer '\0'

[mossmaurice]

Brief feature description

By using c'tor 5 the current implementations cuts off the std::string after each '\0'. Sometimes ''\0' need to be transferred, see #1355.

Detailed information

• Use c'tor 4 which takes an explicit length for the following classes:
  • [ ] UnixDomainSocket
  • [ ] NamedPipe
  • [ ] MessageQueue

[elfenpiff]

@mossmaurice I will have to work soon on the IpcChannel in RouDi and here I will adjust the overall design a bit in that sense that a cxx::vector<uint8_t> will be sent and received and not some kind of string variation. Then this issue should be solved.