Makes port optional in the URL for serverless compute

[jacobphillips99]

Currently the implementation for hosting server-side models relies on binding to a "port" number such as 8000. However, if we want to use cloud-based compute orchestration platforms like Modal, there's no persistent port as the provider handles all the networking. We want to make the port number optional for the URL.

In auto_eval Job SQLModel, policy_server_port is cast as an integer type. In order to prevent database migration, we use -1 as a sentinel value to avoid adding the port to the URL.

See similar PR in auto_eval repo: zhouzypaul/auto_eval#2

[zhouzypaul]

Thanks for the PR! Merged in zhouzypaul/auto_eval#2

Closing this for now as it seems to have more updates than the intended PR. Feel free to open another with the relevant commits!

[jacobphillips99]

apologies! forgot to close after switching base. Thanks for closing.