hivemind-server unavailable when installing from PyPI

[mryab]

Describe the bug
When installing hivemind from PyPI, we can't use the hivemind-server CLI command, as it tries to import from the folder scripts:

$ hivemind-server
Traceback (most recent call last):
  File "/home/mryab/miniconda3/envs/hivemind_env_test/bin/hivemind-server", line 5, in <module>
    from scripts.run_server import main
ModuleNotFoundError: No module named 'scripts'

We should probably change the directory name the way it's done in transformers or fairseq.

To Reproduce
Install hivemind from PyPI and run hivemind-server

Environment

• Python 3.8.8
• hivemind 0.9.0