Also run all builds on approved MRs

Also run all builds on approved MRs

The test job will use the latest stable so all stable lints are included.

The rust docker image already comes with curl, no need to install wget.

This moves compiler caching for incremental builds away from GitLab
caching the whole target/ folder to caching each code unit in S3.
This aleviates the need to zip and unzip and just caches on the fly.

This feature is optional and gated behind the SCCACHE_BIN_URL env

gcc-8-aarch64-linux-gnu is not available in debian 11 (which the rust image uses), so update to gcc-10

Signed-off-by: Jonas Zohren <git-pbkyr@jzohren.de>

Broke due to a timeout and Timo does not like broken tests.
Less testing means less failing tests.

Also, hopefully sytest is less broken now.

- Build release builds for branches "master" and "next"
- Push docker images under different tags, depending on why the pipeline started
  - branch master: push to `latest`
  - branch next: push to `next`
  - tag: push to `$TAG_NAME`

Signed-off-by: Jonas Zohren <git-pbkyr@jzohren.de>

Signed-off-by: Jonas Zohren <git-pbkyr@jzohren.de>

Using `$CI_COMMIT_REF_NAME` means we get `master` for every image build,
which is not very useful/informative. Using `$CI_COMMIT_SHORT_SHA`,
on the other hand, makes it possible to see exactly from which commit an
image was built.

The average german man has a life expectancy of 78.7 years, or 689884.2 hours.
Assuming that Timo is 20 years old, he has rougly 514564.2 hours left on planet earth.
Also assuming that cross release builds took him 25 minutes before,
but 2-2.5x of that with the current release compilation config he wasted roughly an hour waiting for it to complete.
If he continued to work on Conduit for 20 more years (or 175320 hours),
and makes a release compilation about once per day, this means 7305 hours or 304 days wasted waiting for the rust compiler.
By cutting that back down to the original settings, he get's 182 days of his life back.
That's about 0.63% of his remaining life.
182 joyful days he can spend with family and loved ones.

Signed-off-by: Jonas Zohren <git-pbkyr@jzohren.de>