Drop .dtseries.json metadata files

[effigies]

What happened?

We're still emitting both bold.json and bold.dtseries.json for CIFTI outputs. This is a holdover from needing to maintain backwards compatibility in a minor release series while adding required BIDS metadata in the correct place.

We should finish the job and remove .dtseries.json files altogether in 22.1.

Follow-up to #2294.

What command did you use?

blah

What version of fMRIPrep are you running?

22.0.2

How are you running fMRIPrep?

Docker

Is your data BIDS valid?

Yes

Are you reusing any previously computed results?

No

Please copy and paste any relevant log output.

No response

Additional information / screenshots

No response