Dockerfile - Reduce size and pin dependencies

[AndreaGiardini]

Hello :wave:

I reworked a little the Dockerfile to reduce the size of the final image and fix dependencies on external libraries / software

[AndreaGiardini]

@carlodef is it possible to implement the auto-push to https://hub.docker.com/r/cmla/s2p/ ?

Would be nice to have something like:

• Git branch: master -> docker tag: latest
• Git tag: 0.X -> docker tag: 0.X

[carlodef]

Hi @AndreaGiardini yes that would be nice indeed. I'll try to set this up