Add the MessageUI framework #3324

Job	Run time
Lint macOS x86_64	3m 29s
Check formatting	15s
Lint iOS ARMv7s	3m 27s
Check MSRV	55s
Lint visionOS Aarch64 simulator	3m 24s
Lint GNUStep + exceptions	1m 25s
Lint header-translator	29s
Lint test-assembly	28s
Test macOS 15 Aarch64	1m 29s
Compiler UI	45s
Verify header translator output	1m 56s
Assembly tests	53s
Check framework features	0s
${{ ((matrix.test && 'Test') \|\| 'Build') }} ${{ matrix.name }}	0s
Test Compiler-RT	23s
Test GNUStep with libobjc2 v1.9	1m 12s
Test GNUStep with libobjc2 v2.0	1m 20s
Test on iOS simulator w. dinghy	0s
Test GNUStep with libobjc2 v2.1 on nightly	1m 6s
Test GNUStep 32bit	1m 20s
	24m 16s

Provide feedback