enable `pip install` from within the provider

[mateuszsrebrny]

Why

We want ray worker running on provider to be able to get any needed libs from pip before starting the actual computations

How

• On worker side we should be able to run something like this:

   pip install --index-url https://pypi.dev.golem.network/simple redis
  

• We should be able to put pip command into yaml file to execute at the setup phase (for now it is ok to make user write --index-url, it might require hiding later though)

• there is example of how this can be done in https://github.com/golemfactory/golem-kernel-python/tree/ms-misc

Tasks

Beta Give feedback

1. use manifest to allow outbound for pip in cluster manager
2. make sure the pip cmdline works from inside of the worker