Added parsers for CWL input files #676

Job	Run time
CI linters via Tox (lint-readme)	27s
cwl-utils release test	6m 55s
CI tests via Tox (3, 8, lint)	31s
CI linters via Tox (pydocstyle)	22s
CI tests via Tox (3, 8, unit)	2m 29s
CI tests via Tox (3, 8, bandit)	42s
CI tests via Tox (3, 8, mypy)	1m 5s
CI tests via Tox (3, 9, lint)	33s
CI tests via Tox (3, 9, unit)	2m 10s
CI tests via Tox (3, 9, bandit)	45s
CI tests via Tox (3, 9, mypy)	1m 3s
CI tests via Tox (3, 10, lint)	36s
CI tests via Tox (3, 10, unit)	2m 46s
CI tests via Tox (3, 10, bandit)	43s
CI tests via Tox (3, 10, mypy)	42s
CI tests via Tox (3, 11, lint)	24s
CI tests via Tox (3, 11, unit)	2m 30s
CI tests via Tox (3, 11, bandit)	33s
CI tests via Tox (3, 11, mypy)	46s
CI tests via Tox (3, 12, lint)	40s
CI tests via Tox (3, 12, unit)	2m 38s
CI tests via Tox (3, 12, bandit)	55s
CI tests via Tox (3, 12, mypy)	59s
	31m 14s

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