Support regular text completion mode & expand

[eckartal]

Problem

• Users need more flexibility beyond instruct models, including regular text completion mode.
• Additionally, running as a server with third-party UI compatibility via multiple API integrations would improve usability.

Success Criteria

• Add regular text completion mode alongside instruct models.
• Enable server mode for remote access.

Additional Context

[Source](https://www.reddit.com/r/LocalLLaMA/comments/1isazyj/comment/mdf4b76/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button)