Improve Connection Path parsing

The connection path format is defined in Vol1 3-5.5.1.10: Connection Path.
There, a strict ordering of segments is specified, where electronic keys go first, followed by application paths, and finished by data and network segments. The connection path parser currently does not enforce such an ordering and will accept, for instance, the electronic, at any location within the path.

it would actually be pretty cool to have an imperative parse instead of the huge switch-case, like:

while (consume_electronic_key(path))
{
  push_path();
  while (consume_network_segment(path));
  if (!parse_port_segment(path))
  {
    pop_path();
    break;
  }
}

consume_electronic_key(path);
consume_network_segment();
expect_application_path();
while (consume_application_path())
{
  
}
consume_simple_data_segment();
while (consume_network_segment(path));