WebClient: Setup page

I don't think we need to repeat [Prerequisistes](https://0xmiden.github.io/miden-docs/imported/miden-tutorials/src/web-client/create_deploy_tutorial.html#prerequisites) in each tutorial.
Instead, we should have a WebClient -> Setup subpage that outlines the prerequisistes once and for all.

Look at the existing tutorial structure in the repository, particularly the WebClient tutorials. Identify where prerequisites are currently repeated. Create a new 'Setup' subpage under WebClient that consolidates these prerequisites. Verify the change by checking the generated documentation links and ensuring the tutorials now reference the single setup page.

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