Add CITATION.cff based on JOSS paper.md

[yarikoptic]

The actual script is pushed to

https://github.com/nipy/heudiconv/blob/paper-joss/tools/paper-to-citationcff

which was ran and then record was tuned up.

edit: purpose - to satisfy JOSS requirement to have release with a matching list of authors. See https://github.com/openjournals/joss-reviews/issues/5839#issuecomment-2088474424 and there on

[yarikoptic]

FWIW -- CI validated fine:

Run cffconvert --validate
Citation metadata are valid according to schema version [1](https://github.com/nipy/heudiconv/actions/runs/9101979981/job/25020506168?pr=758#step:6:1).2.0.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 82.04%. Comparing base (6ace2f6) to head (75932d7).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #758 +/- ## ======================================= Coverage 82.04% 82.04% ======================================= Files 42 42 Lines 4205 4205 ======================================= Hits 3450 3450 Misses 755 755 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[github-actions[bot]]

:rocket: PR was released in v1.1.2 :rocket: