Add phantom test, using 3 phantoms

[koenhelwegen]

This PR adds integration tests using three basic phantoms, generated with https://github.com/ecaruyer/phantomas.

To Do

• [ ] Currently CATO uses the FreeSurfer utility mri_info, complicating any CI. I would be in favor of removing this dependency -> we'll do this later
• [x] There is still a minor issue with relative paths to the config files that needs to be resolved.
• [ ] Add to Github Actions (see https://github.com/mathworks/ci-configuration-examples).

Phantoms

Phantom sub0 contains four regions of interest, and a single fiber stream connecting regions 2 and 4 (so regions 1 and 3 are not connected to anything, and there are no complications in terms of crossing fibers). This is a basic check to see if all the code runs and a correct connectivity matrix is generated. As a bonus, it checks the 'edge case' of unconnected ROIs.

Phantom sub1 contains the same four regions, but now with two fiber streams. The fiber streams don't get close: This should catch any weirdness with flipped gradient directions etc.

Phantom sub2 is a crossing fiber example. Where the first two are tested with DTI, GQI and GQI_DTI, this one is only tested with GQI and GQI_DTI as reconstruction methods.

[SiemondeLange]

• There is still a minor issue with relative paths to the config files that needs to be resolved.

To solve this issue, I would suggest to use the mfilename function:

configFile = fullfile(fileparts(mfilename('fullpath')), ...
'assets/', phantomSub, '/misc/cato_structural_config.json');

[koenhelwegen]

To solve this issue, I would suggest to use the mfilename function

Fixed in 1fa4496.

As discussed, we'll resolve the FSL dependency later and add this to CI at that point, meaning this PR is ready to be merged from my site!