WIP [9.1?] feat: remove the TransformationDB.DataFiles table #12917

Job	Run time
check (pytest --runslow -k 'not test_BaseType_Unicode and not test_nestedStructure')	18m 7s
check (pylint -j 0 -E src/)	3m 58s
check (mypy)	2m 44s
pre-commit	1m 0s
pycodestyle	5s
Pylint for Python 2.7 in Pilot files	35s
shellcheck	4s
	26m 33s

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