[SQL/MEG] Add the MEG CTF head shape tables

[MaximeBICMTL]

Description

The MEG CTF format uses a headshape.pos file to register the head shape of the participant. This file is CTF-specific but BIDS-standard (the BIDS MEG specification basically allows to use native files of all specific data types), and is usually shared across all the MEG acquisitions of a session.

This PR adds some tables to register this data in the LORIS physiological database and link it to the relevant MEG files.

The headshape.pos file format is unfortunately very sparsely documented. It is a textual file format whose contents looks like this:

85
1		5.60644227	-6.38055462	0.79194871
2		8.06310971	-4.72750212	0.59046631
3		7.58675759	-5.78050209	3.05185917
...
NAS	8.57169649	-0.14219376	-3.33998151
LPA	-0.58286578	7.02263278	0.27529669
RPA	-1.40471662	-7.10183109	0.57320080

The first line is the number of points. The coordinates are in centimeters. It might be useful to use a proper physiological_coord_system in the future, but this can easily be added later IMO, so I'd like to start by merging this minimal implementation.

Testing

• ✅ Ran the SQL patch on Raisinbread.
• ✅ Use these tables in my BIDS MEG import LORIS Python branch.