Shrink/Optimize Dockerfile

[tomodachi]

Changes Shrink the resulting image with 70mb by removing unused dependencies and merging several
runs to a single layer.

[tomodachi]

I tested compiling the 4 target arches in the example in the Dockerfile from within the container after doing my modifications and it all succeeded so believe it's all good.

[roderickvd]

I don't use Docker but sounds good to me! Would you resolve the conflict?

[kingosticks]

The only comment I have is that to ensure it's still as easy as possible to comment lines out and just compile the platform you want. I think you got that with the new lines but I didn't check properly sorry.

[tomodachi]

@roderickvd Fixed the conflict (just a version bump for rust in rustup)

@kingosticks It works exactly the same before, so no change in how you compile to specific platforms.

[kingosticks]

Ok, great.

[tomodachi]

Hi, anything more I can help out with to get this merged?

[photovoltex]

Don't think so, as the others seem to be fine with these changes. I will probably merge it during the day.

Could you maybe just quickly check if the docker images are still fine and report back? It seems we currently have some compilation issues on dev, so it would be nice to know if the images are impacted or not^^. (unrelated to the PR, but nice to know)

[photovoltex]

Just checked myself. As bindgen-cli and clang are getting installed the issue that occurs in the CI doesn't affect the image creation.