ci: use fdo ci-template

Main feature is to install all the packages and tools we need to the container image, saving us to download and build them at each run.

I used the same strategy as gstreamer-rs's ci: rely solely on container for caching instead of using gitlab's cache. This seems to be faster now that all tools are in the image as saving and restoring the cargo and target cache was taking a while. It also reduces the data transfers between runners which are the most expensive part of the bill for the ci infrastructure.

The image needs to be manually updated when a new version of Rust is released. This is easily done by bumping FDO_DISTRIBUTION_TAG. Doing so also reduce the chance of CI breaking behind our back because of Rust or tools updates.