Binary embeddings final cleanup

[simonw]

I merged this a bit hastily:

• Binary embeddings #254
• Support for embedding binary files #253

I should double-check that the documentation holds up, especially with respect to the plugins I'm about to ship.

• Documentation for binary embeddings --binary option
• Documentation for writing a binary embedding plugin
• Feature CLIP quite extensively in docs

https://github.com/simonw/llm-clip

[simonw]

I'm going to push an alpha so I can ship alphas of the plugins.

[simonw]

With the alpha shipped I can now build the two plugins - llm-clip and llm-imagebind - and use those to finish testing and documenting everything.

[simonw]

Also need to add supports_binary = True and supports_text = True to the embedding plugin docs.

[simonw]

I'm not going to build llm-imagebind yet.

[simonw]

The rest will happen here:

• Ship 0.10, then ship a llm-clip non-alpha #270