Fix: tauri prereqs link + mention localhost:8080 on Getting Started Page

[jroddev]

The Tauri link from Getting Started now gives a 404.
Looks like it's changed from https://beta.tauri.app/guides/prerequisites/ to https://beta.tauri.app/start/prerequisites/

I also added that dx serve will serve Web targets at http://localhost:8080 as it wasn't clear from the getting started page and isn't mentioned in the generated app src or dx serve log. Though the dx serve log may be a better place for it.

Dioxus @ v0.5.4 [16:33:50]

    > Hot Reload Mode: RSX
    > Watching: [ src, assets, Cargo.toml, Dioxus.toml ]
    > Custom index.html: None
    > Serve index.html on 404: True

    > Build Features: [ server ]
    > Build Profile: Debug
    > Build took: 16580 millis

2024-04-26T06:36:58.352975Z  INFO dioxus_fullstack::render: Rebuilding vdom
2024-04-26T06:36:58.353099Z  INFO dioxus_fullstack::render: Suspense resolved
spinning up hot reloading
connecting to "/home/.../dioxus-0-5-fullstack-test/target/dioxusin"
Connected to hot reloading 🚀
hot reloading ready
🔥 Hot Reload WebSocket connected
🔮 Finding updates since last compile...
finished
2024-04-26T06:42:18.739002Z  INFO dioxus_0_5_fullstack_test: Server received: Hello from the server!

[ealmloff]

Thank you!