Add `keys` to ModuleManager #11

Job	Run time
Common-Pull-Request / license_and_format	40s
Common-Pull-Request / test_library (gcc-11)	5m 16s
Common-Pull-Request / test_build_docs	52s
Common-Pull-Request / test_library (clang-11)	4m 50s
	11m 38s

Provide feedback