Migrate ORM to pathlib.Path (path PR 2)

[MaximeBICMTL]

Builds on #1349

Description

Migrate the ORM models and queries from the str type for paths, to pathlib.Path, and consolidate the ORM around the path naming for paths (instead of path, rel_path, location...).

Testing

• Ran the DICOM study importer manually and checked the result.
• PR code is strictly typed and change is rather straightforward.

Detailed changes

Add a new StringPath decorator to translate back and forth between SQL strings and Python paths.

Renamings:

• DbDicomArchive.source_location -> DbDicomArchive.source_path
• DbDicomArchive.archive_location -> DbDicomArchive.archive_path
• DbFile.rel_path -> DbFile.path
• DbMriProtocolViolatedScan.file_rel_path -> DbMriProtocolViolatedScan.file_path
• DbMriUpload.upload_location -> DbMriUpload.upload_path
• DbMriUpload.decompressed_location -> DbMriUpload.decompressed_path
• DbMriViolationLog.file_rel_path -> DbMriViolationLog.file_path

Type changes (from str to Path):

• DbDicomArchive.source_path
• DbDicomArchive.archive_path
• DbFile.path
• DbMriProtocolViolatedScan.file_path
• DbMriUpload.upload_path
• DbMriUpload.decompressed_path
• DbMriViolationLog.file_path
• DbPhysioChannel.file_path
• DbPhysioCoordSystem.file_path
• DbPhysioEventFile.file_path
• DbPhysioFile.path

[jeffersoncasimir]

I proofread the Files changed and it LGTM!