Add `.splups` file reader #195

Job	Run time
precommit / Load tox environments	5s
test / Load tox environments	10s
precommit / pre-commit (ubuntu-latest)	35s
test / py311 (macos-latest)	5m 35s
test / py311 (windows-latest)	11m 9s
test / py39 (ubuntu-latest)	7m 45s
test / py310 (ubuntu-latest)	7m 56s
test / py311 (ubuntu-latest)	7m 41s
docs / Load tox environments	5s
test_database_v9 / Load tox environments	7s
test_full_database / Load tox environments	6s
docs / build_docs (ubuntu-latest)	6m 45s
test_full_database / py311 (ubuntu-latest)	10m 45s
test_database_v9 / py311 (ubuntu-latest)	3m 21s
publish	0s
	1h 2m 5s

Provide feedback