Add option to add custom URLs/models

[azidancorp]

I am currently just using the copy-prompt method now, but this is hopefully a simple change. Also adding the custom url/slug will reduce burden to update the extension frequently each time new LLMs are released

Main reasons:

1. Primarily I'd like to use poe.com, which has a wide variety of models from all providers (often at discounted prices). It has a basic pattern of poe.com/model-slug

2. ChatGPT only has 4o from the extension at the moment, but I'd really like to use o3/o4-mini-high

3. Sometimes I'd like to use a custom GPT/Bot/Gem etc on these websites, with their own url suffix

4. Theres plenty of other webapps, Qwen and Meta for example all with their own models.

[robertpiosik]

Hi, each of the providers require manual work on implementation, it is dictated by differences in the way they're all written.

1. I'm against promoting services like poe
2. ChatGPT will be fully supported soon
3. Qwen only accepts long prompts via clipboard paste event but we set them directly on the field therefore I was unable to get it working yet. Meta heavily limits prompt length.

My suggestion is using OpenRouter provider, you have all the models there.

You can also run local instance of Open WebUI.