In this PR:

• I removed all the pip installable packages from the deeprank.yml and I moved them back into the pyproject.toml file. This way they will be package together with the package on pip, and pip install deeprank2 will take care of installing them all.
• I found a way for installing pip packages within the env defined in the dockerfile. After this PR will be merged, I will do a new pip release (which will contain the pip dependencies) and I'll delete the deeprank2-docker.yml and requirements-docker.txt files, since they are not needed anymore (I will pip install deeprank2 together with its pip dependencies in the dockerfile).
• No need to update the instructions for the installation.