feat (ai/provider): add Google Vertex provider

[lgrammel]

Summary

Adds an AI SDK provider for Google Vertex. It supports text generation and streaming for text and image inputs.

Tasks

• implement provider
  • better env param errors
  • support streaming
  • support image inputs
  • map finish reason
  • support settings
• test
• examples
• docs
  • provider page
  • add to overview pages
• changesets

Future Work

• support tool calling

[li2109]

Can you also add googleAuthOptions to GoogleVertexProviderSettings?
context: https://stackoverflow.com/questions/77944196/vertex-ai-googleautherror-in-nodejs

BTW, it would be great if preview models could be supported like gemini-1.5-pro and flash.

const authOptions = {
        credentials: {
            client_email: process.env.GOOGLE_VERTEX_CLIENT_EMAIL,
            private_key: process.env.GOOGLE_VERTEX_PRIVATE_KEY!.replace(/\\n/g, "\n"),
        }
    }

    const vertex_ai = new VertexAI({
        project: process.env.GOOGLE_VERTEX_PROJECT!,
        location: process.env.GOOGLE_VERTEX_LOCATION,
        googleAuthOptions: authOptions,
    });
const model = vertex_ai.preview.getGenerativeModel({ model: 'gemini-1.5-flash-001' })

Thank you!

[lgrammel]

@li2109 flash etc should be supported (strings can be entered as model). can you file an issue for the googleAuthOptions so it does not get lost?

[li2109]

Can you also add googleAuthOptions to GoogleVertexProviderSettings? context: https://stackoverflow.com/questions/77944196/vertex-ai-googleautherror-in-nodejs

Thank you!
#1773