Proposed changes v5: functionalMRIAcquisition schema

[Alixbonard]

Pull request: #34
Changes:

• specimentOrientation is removed
• delayAfterTrigger, delayTime, fieldMap, sbref and structureMRI should be more discussed .

12/02/2026:

• delayAfterTrigger is removed
• delayTime is optional
• fieldMap, sbref and structureMRI are becoming distortion correction, motion correction, registration data respectively
• numberofVolumeDiscardedbyUser (?)