ci: Use fdo's ci-template to build docker images
While at it, update Android NDK to latest r23b. Better test recent NDK that people are likely to be using than an ancient one.
TODO:
-
Run job as user instead of root: https://gitlab.freedesktop.org/freedesktop/ci-templates/-/issues/48 -
Port coverity image: Removed that special image and instead redownload the analysis too in the job.