docker build action about ci-actions

[lsf37]

This is blocked on the machine queue, because the "internal" build options refer to the repo that provides the machine-queue command, which is being re-done.

If necessary we can make some progress on everything that does not use this, but at least Bamboo expects that command to be there for hardware tests.

[lsf37]

Now unblocked, machine queue dependency is no longer required in the docker base images.

First steps in seL4/seL4-CAmkES-L4v-dockerfiles#38

[lsf37]

One remaining blocker after the toolchain upgrade: one of the SCHED tests consistently fails with clang11 on pc99.

[lsf37]

The main images have been building on pull request for a while (with seL4/seL4-CAmkES-L4v-dockerfiles#39). RISCV has been removed as separate image and the sysinit images are currently unmaintained.