Add docker instructions for developers in the docs

[RemDelaporteMathurin]

Detailed instructions for contributors using Docker could be beneficial (which dependencies image should we use, which Docker command, etc...)

Maybe I'm just being lazy (or have a really bad memory) but I keep forgetting the syntax for running a container with shared volumes.

Plus, the ukaea/paramak:dependencies doesn't seem to be specified anywhere in the installation section.

Just adding the following command would save a lot of time (in my opinion):

docker run -it -v $(pwd):/home/shared ukaea/paramak:dependencies

For windows: docker run -it -v ${PWD}:/home/shared ukaea/paramak:dependencies