feat(start-vite-plugin): copy the TanStack Start specific plugin logic into its own standalone vite plugin

[SeanCassiere]

A new @tanstack/start-vite-plugin that only has the vite plugin logic related to TanStack Start. Currently, this means, only the prepending of the "use server" directive to createServerFn calls.

I've added a couple more tests and logic to handle cases where:

• A destructured createServerFn import is renamed like import { createServerFn as serverFn } ....
• A star import is used like import * as TanStackStart ...; TanStackStart.createServerFn.

This PR doesn't remove any existing functionality from the @tanstack/router-vite-plugin package. In a separate PR I'll remove the Start logic from the @tanstack/router-vite-plugin package will be removed and patch the @tanstack/start package.

[nx-cloud]

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