Add dataset-level description option

[tsalo]

I'm starting to work on CuBIDS, which is useful for annotating variant acquisitions in a BIDS dataset (e.g., adding an acq entity if some runs of a task have X volumes and some have Y volumes in the dataset). It would be great to have an option in pybids-reports that generates a description that accounts for variants by specifically looking at the acq field and reporting across subjects.

For example, let's say we have a dataset like this:

sub-01/
    func/
        sub-01_task-rest_acq-100volumes_bold.nii.gz
sub-02/
    func/
        sub-02_task-rest_acq-100volumes_bold.nii.gz
sub-03/
    func/
        sub-03_task-rest_acq-90volumes_bold.nii.gz

In the current version of pybids-reports, we would end up with two patterns in the BIDSReport report Counter: one that describes subjects 01 and 02, and a second one that describes subject 03. My proposal is a parameter in BIDSReport that would describe the whole dataset, treating the different acq values as different variants on the same task (assuming all other entities are the same).

Something like:

For session 01:
MR data were acquired using a 3-Tesla Siemens Prisma MRI scanner.
In two subjects, one run of resting-state fMRI data were collected (). Each run was XX minutes in length, during
which 100 functional volumes were acquired.
In one subject, one run of resting-state fMRI data were collected (). Each run was XX minutes in length, during
which 90 functional volumes were acquired.

[Remi-Gau]

treating the different acq values as different variants on the same task (assuming all other entities are the same)

yeah that was my thought when I started reading the beginning of your issue.