feat(docker/cros-tast): Add package to cros-tast image

[nuclearcat]

Right now we are installing python3-junitparser by apt, it is better to pre-build it with docker image.

[a-wai]

LGTM, please add fluster_parser as well (see https://github.com/kernelci/kernelci-core/pull/2673#discussion_r1760774951)