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.

BEREMIZ_OBJS = $(BEREMIZSRC:.c=.o)

all: warn some_binary
	@echo "*** all done ***"

warn:
	@echo "*** Sample Makefile, does nothing ***"

some_binary: $(BEREMIZ_OBJS)
	@echo "* Would link $^ -> $@"

%.o: %.c
	@echo "* Would compile $< -> $@"