Convert os.path to pathlib based Paths #1084

Job	Run time
Build MDANSE and run tests on ubuntu-latest	6m 59s
Build MDANSE and run tests on ubuntu-latest	5m 11s
Build MDANSE and run tests on ubuntu-latest	4m 51s
Build MDANSE and run tests on ubuntu-latest	5m 23s
Build MDANSE and run tests on windows-latest	10m 14s
Build MDANSE and run tests on windows-latest	11m 4s
Build MDANSE and run tests on windows-latest	10m 42s
Build MDANSE and run tests on windows-latest	10m 42s
Build MDANSE and run tests on macOS-latest	6m 53s
Build MDANSE and run tests on macOS-latest	4m 48s
Build MDANSE and run tests on macOS-latest	3m 36s
Build MDANSE and run tests on macOS-latest	3m 45s
	1h 24m 8s

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