feat: allow filesystem apps to specify a ci-only requirements.txt #1934

Job	Run time
ci (kubernetes, ./tests/bin/ci.sh -e 'test(7.\|8.)\|python.*', ubuntu-latest)	1m 47s
ci (kubernetes, ./tests/bin/ci.sh -i 'test7.' -e 'test7(b.\|c.\|d.\|e.\|f.\|g.\|h.)', ubuntu-la...	2m 35s
ci (kubernetes, ./tests/bin/ci.sh -i 'test7(b.\|c.\|d.\|e.\|g.\|h.)', ubuntu-latest)	2m 31s
ci (kubernetes, ./tests/bin/ci.sh -i 'test7f.*', ubuntu-latest)	2m 32s
ci (kubernetes, ./tests/bin/ci.sh -i 'test8.*', ubuntu-latest)	1m 58s
ci (kubernetes, ./tests/bin/ci.sh -i 'python-code.*', ubuntu-latest)	1m 46s
ci (kubernetes, ./tests/bin/ci.sh -i 'python-language.*', ubuntu-latest)	1m 52s
ci (kubernetes, ./tests/bin/ci.sh -i 'python-universal.*', ubuntu-latest)	1m 58s
ci (kubernetes, ./tests/bin/go.sh, ubuntu-latest)	1m 6s
ci (kubernetes, ./tests/bin/pipelines.sh, ubuntu-latest)	2m 37s
ci (local, ./tests/bin/ci.sh -e 'test(7.\|8.)\|python.*', ubuntu-latest)	1s
ci (local, ./tests/bin/ci.sh -i 'test7.' -e 'test7(b.\|c.\|d.\|e.\|f.\|g.\|h.)', ubuntu-latest)	1s
ci (local, ./tests/bin/ci.sh -i 'test7(b.\|c.\|d.\|e.\|g.\|h.)', ubuntu-latest)	1s
ci (local, ./tests/bin/ci.sh -i 'test7f.*', ubuntu-latest)	1s
ci (local, ./tests/bin/ci.sh -i 'test8.*', ubuntu-latest)	1s
ci (local, ./tests/bin/ci.sh -i 'python-code.*', ubuntu-latest)	1s
ci (local, ./tests/bin/ci.sh -i 'python-language.*', ubuntu-latest)	1s
ci (local, ./tests/bin/ci.sh -i 'python-universal.*', ubuntu-latest)	1s
ci (local, ./tests/bin/go.sh, ubuntu-latest)	1s
ci (local, ./tests/bin/pipelines.sh, ubuntu-latest)	1s
	20m 52s

Provide feedback