Small QOL improvements

[mariuskoeppen]

This will add some quality-of-life improvements:

• Add default Trunk.toml file from the trunk repo with some basic settings preconfigured.
• Get prompted what channel (stable/nightly) to use and configure the files accordingly.
• Get prompted if default VS Code editor settings should be added. This mainly configures the rustfmt command. In future we could add support for other text editors.
• Change default from CSS to SCSS. In my opinion there are no downsides to SCSS over CSS.

[gbj]

This looks good to me overall! My one question has to do with the VS Code settings: if the user does not have leptosfmt installed, how does rust-analyzer handle this?

[mariuskoeppen]

When you don't have leptosfmt installed you will get the following error on saving:

[Error - 8:20:34 AM] Request textDocument/formatting failed.
  Message: Failed to spawn cd "[project_path]/src/components" && "leptosfmt" "--stdin" "--rustfmt"
  Code: -32603

Only formatting will not work, otherwise everything is fine. We could mention in the Readme that leptosfmt should be installed manually.

[gbj]

Okay, thanks.

[mariuskoeppen]

This PR now also bumps leptos from 0.6 to 0.7

[gbj]

Thanks very much!