Output motion transforms in BIDS Derivatives

[effigies]

Affine transforms from each original BOLD volume to the BOLD reference volume should be stored in the derivatives.

For now let's use a simple format that roughly corresponds to an array such that:

# affine : list of 4x4 matrices
# all_params : n x 12 matrix
affine[i][:3] = all_params[i, :].reshape(3, 4)

Part of #2207.

[Lestropie]

This will require two small applications for inclusion in the workflow:

1. Generation of a single file of some format that includes the affine transformation (likely in the 1x12 ITK format) for every volume.

2. Load this file, select a specific volume, and export a text file that conforms to the ITK format.

[effigies]

@Lestropie

fmriprep/.circleci/config.yml

Lines 457 to 469 in 6ba165e

	fmriprep-docker -i nipreps/fmriprep:latest \
	-e FMRIPREP_DEV 1 --user $(id -u):$(id -g) \
	--network none \
	--config $PWD/nipype.cfg -w /tmp/${DATASET}/work \
	/tmp/data/${DATASET} /tmp/${DATASET}/derivatives participant \
	--fs-subjects-dir /tmp/${DATASET}/freesurfer \
	${FASTRACK_ARG} \
	--output-layout legacy \
	--sloppy --write-graph --mem-mb 14336 \
	--skull-strip-template OASIS30ANTs:res-1 \
	--output-spaces fsaverage5 fsnative \
	--use-plugin /home/circleci/src/fmriprep/.circleci/legacy.yml \
	--nthreads 4 -vv