Prevent docker build layer cache invalidation

[kpine]

The Dockerfile is including all files in the project, which means touching any file in the project (README, docs, docker root files, etc) invalidates practically all of the cached docker layers and triggers a rebuild of all libraries and applications.

Manually copy the needed files instead of the entire project. Note that using .dockerignore alone is not possible because it would prevent copying some files into the image that are necessary but unrelated to the application builds.

[kpine]

Alternatively, all the library/application files could be moved to a subdir, and that copied.

[Fishwaldo]

Thanks