ci: new build-base Dockerfile and workflow
The whole CI is refactored. The following problems are solved:
1. Couldn't test base image locally without overriding the old one.
The testing stage is run in two ways depending on whether some of the docker-related files were changed.
If they didn't (most likely), testing stage is run on the latest
docker image as it used to.
Otherwise, the docker image is rebuilt locally and tested. This is done
by using image:pull_policy option, see [1].
It also makes a problem of using protected credentials irrelevant.
2. Gitlab caching used to be slow
Stupid gitlab caching (see [2]) wasted on (un)zipping cache 4 minutes (of 6 total). Now it's replaced with a manual one: an archive (tar) is placed in a docker volume on a self-hosted gitlab runner with no compression.
3. Speed up fetching git.
The tarantool-sys submodule requires a tag to be built correctly, but
using shallow clones prevented that. We used to work-around it by
specifying GIT_DEPTH: 0, but that's sub-optimal too. This patch
introduces an elegant yet reliable solution:
until git describe; do git fetch --deepen 100; done4. No fine-grained time tracking was available
Gitlab only shows the total time of step_script without splitting it
into particular commands. This problem is solved by incorporating
collapsible log sections feature, see [3]. It makes logs fancy too.
Refs: