Add ExtendedCall to PLCObject as a replacement of RemoteExec and reflect it in eRPC interface.

ExtendedCall is a generic remote procedure call that runtime code can register to and that IDE extensions can call.
For example a fieldbus extension can use ExtendedCall to browse the fieldbus devices connected to the runtime.

input,smta,1,DINT,0
input,smtb,1,DINT,1
input,smtc,1,DINT,2
input,smtd,1,DINT,3
input,smte,1,DINT,4
output,smtf,1,False,DINT,0
output,smtg,1,False,DINT,1
output,smth,1,False,DINT,2
output,smti,1,False,DINT,3
output,smtj,1,False,DINT,4