Update/release computational stimulus features

[mih]

Register @chrhaeusler work on the low-level confounds

Orthogonalize against `@mih work on face detection.

There were some relevant changes in pHash https://pypi.org/project/ImageHash/4.0/ that broke the pHashes (new values are returned), but @chrhaeusler verified that despite the value difference, there is not significant change.

[chrhaeusler]

It's done:
psychoinformatics-de/studyforrest-data-confoundsannotation,
and imported / meged here:
psychoinformatics-de/studyforrest-data-annotations

Open:
both datasets are (probably) not referenced anywhere yet and might benefit from being available at a hoster that provides an DOI?