FEATURE: support o1 reasoning models

[merefield]

This PR introduces support for o1-preview and o1-mini advanced reasoning models.

Must be used in basic mode.

e.g.

Note there are significant limitations to these models including:

• no system prompt support (so you can't customise the character of your bot)
• no tool support (so you can't use tools like searching your local forum)
• no changing of model parameters.