Remove Ice for Objective-C

[bernardnormier]

This PR removes Ice for Objective-C.

Note: we still have some Objective-C and Objective-C++ code in cpp and swift. I also kept the Objective-C and Objective-C compilation rules in Make.project.rules as they are used when building cpp for iOS.

[externl]

Looks good. The ci action in the .github folder should also be updated to remove objc.

[pepone]

Looks good, I think we can also remove the rules for .m and .mm from

ice/config/Make.project.rules

Lines 130 to 148 in df5e937

	ifneq ($(filter %.mm,$4),)
	# Rules to build Objective-C++ sources from <srcdir>
	$3/%.o: $1/%.mm
	$3/%.o: $1/%.mm
	$(E) "Compiling [$8-$9] $$<"
	$(Q)$(or $($8_cxx),$(platform_cxx)) $(CXXFLAGS) $(call depend-cppflags,$3/$$*.Td,$$@)\
	$(strip $6) $(CPPFLAGS) -std=c++17 -c $$< -o $$@
	$(Q)$(MV) $3/$$*.Td $3/$$*.mm.d
	endif
	ifneq ($(filter %.m,$4),)
	# Rules to build Objective-C sources from <srcdir>
	$3/%.o: $1/%.m
	$3/%.o: $1/%.m
	$(E) "Compiling [$8-$9] $$<"
	$(Q)$(or $($8_cxx),$(platform_cxx)) $(CXXFLAGS) $(call depend-cppflags,$3/$$*.Td,$$@)\
	$(strip $6) $(CPPFLAGS) -c $$< -o $$@
	$(Q)$(MV) $3/$$*.Td $3/$$*.m.d
	endif

[bernardnormier]

Looks good, I think we can also remove the rules for .m and .mm from

We can't and shouldn't. See the main description of this PR.