"ODE" quantities and user defined external sources #586

Job	Run time
Save-PR-Number	5s
Formatting	10s
CPU-GNUmake	1m 31s
CPU-CMake (ubuntu-latest, Release, EB-OFF)	3m 48s
Lint-codeql	23m 41s
Lint-clang-tidy (EB-OFF)	23m 34s
CPU-CMake (ubuntu-latest, Release, EB-ON)	3m 46s
Lint-clang-tidy (EB-ON)	23m 33s
CPU-CMake (ubuntu-latest, Debug, EB-OFF)	3m 40s
Lint-codespell	8s
CPU-CMake (ubuntu-latest, Debug, EB-ON)	3m 46s
CPU-CMake (macos-latest, Release, EB-OFF)	3m 49s
CPU-CMake (macos-latest, Release, EB-ON)	3m 28s
GPU-CUDA (11.4)	21m 52s
GPU-HIP	13m 22s
GPU-SYCL	21m 50s
	2h 32m 3s

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