Improve Getting Started guide

[vasfvitor]

          > What's it's not clear to me tho is: how would one install sveltekit cleanly, as CTA creates a vite project. What I did was to install sveltekit and copy over it's contents and mix imports. But that's far from ideal.

Create a plain sveltekit app, add the tauri cli to it, run tauri init. (see v1 docs). I did not include this because the other config guides do not have it yet either and therefore considered it out of scope for this pr

Originally posted by @FabianLars in #2121 (comment)

[simonhyll]

Based on the recent CTA SvelteKit discussions lets wait for those to conclude before we take action on this.

[vasfvitor]

to clarify, the intention is not specifically to improve the sveltekit guide, but to give a context on how to create/scaffold a tauri app from scratch before referencing the framework guides, except vite, that is configured by default. I remember reading something in your website, along the lines of how the folders can be named backend and frontend or else.

[vasfvitor]

I think we have the manual guide somewhere