Hauke has stopped working on RIOT for some time now and other
maintainers agreed to step up to take over the steering / contact job
during the VMA. This change replaces Hauke by benpicco and maribu as
contact as agreed upon.
- drop completed tasks
- drop tasks that make no sense anymore (e.g. cleanup up MIPS, as
MIPS was dropped or improving xtimer, as it was superseded by
ztimer)
