fix: Update missing metadata to qMRI sequences

[effigies]

After merging bids-standard/bids-specification#2020, attempting to update the schema for the validator produces:

  ┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
  │ qmri_mtsat                                                                                                      │
  └─────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
    SIDECAR_KEY_REQUIRED -               /sub-01/anat/sub-01_flip-1_mt-off_MTS.ni                                    
    RepetitionTimeExcitation             i.gz                                                                        
                                                                                                                     
    SIDECAR_KEY_REQUIRED -               /sub-01/anat/sub-01_flip-1_mt-on_MTS.nii                                    
    RepetitionTimeExcitation             .gz                                                                         
                                                                                                                     
    SIDECAR_KEY_REQUIRED -               /sub-01/anat/sub-01_flip-2_mt-off_MTS.ni                                    
    RepetitionTimeExcitation             i.gz                                                                        
  ┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
  │ qmri_sa2rage                                                                                                    │
  └─────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
    SIDECAR_KEY_REQUIRED - NumberShots   /sub-01/fmap/sub-01_flip-1_inv-1_TB1SRGE                                    
                                         .nii.gz                                                                     
                                                                                                                     
    SIDECAR_KEY_REQUIRED - NumberShots   /sub-01/fmap/sub-01_flip-2_inv-2_TB1SRGE                                    
                                         .nii.gz                                                                     
  ┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
  │ qmri_vfa                                                                                                        │
  └─────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
    SIDECAR_KEY_REQUIRED -               /sub-01/anat/sub-01_flip-1_VFA.nii.gz                                       
    RepetitionTimeExcitation                                                                                         
                                                                                                                     
    SIDECAR_KEY_REQUIRED -               /sub-01/anat/sub-01_flip-2_VFA.nii.gz                                       
    RepetitionTimeExcitation                                                                                         
                                                                                                                     
    SIDECAR_KEY_REQUIRED -               /sub-01/fmap/sub-01_acq-tr1_TB1AFI.nii.g                                    
    RepetitionTimeExcitation             z                                                                           
                                                                                                                     
    SIDECAR_KEY_REQUIRED -               /sub-01/fmap/sub-01_acq-tr2_TB1AFI.nii.g                                    
    RepetitionTimeExcitation             z  

In most cases, the problem is that RepetitionTime is used instead of RepetitionTimeExcitation in qMRI sequences. I updated across the board, even for those where it is not a required field.

For qmri_sa2rage, the NumberShots field is required, but absent. I don't know how to derive it; there's nothing in the paper (doi:10.1002/mrm.23145), so I just set it to 1.

@agahkarakuzu @ChristophePhillips This affects examples you've provided. Can you please review these changes?