ENH: Overhaul fit workflow with upstream fmriprep changes

[mgxd]

This brings the fit workflow more in line with current (25.2.x) fmriprep - changes include:

• Removes movpar / rmsd files from HMC workflow, which can be calculated on the fly from the motion transforms
• Increases metadata documenting:
  • which files (sbrefs, bold) were used to generate the reference bold images.
  • if bbregister or mri_coreg were used for bold <-> anat coregistration
• Strips out bold validation into a reusable workflow.

Depends on nipreps/niworkflows#1011