* Spun out docker

Remove docker from Makefile.release so we can actually release.
Unify the mips stuff, now that docker is gone.
Update the docs to reflect this.

See #4858
Signed-off-by: Miek Gieben <miek@miek.nl>

* Update test as well
Signed-off-by: Miek Gieben <miek@miek.nl>