Pull out CLI configs into a separate library

[ealmloff]

This PR pulls out the CLI config into a separate library so that we can more easily integrate the config into internal libraries that need to read the config at runtime during dev mode. In the future this will let us read something like the assets path that is supplied in the config inside of the fullstack crate to serve the correct assets in both web and fullstack mode. Overall this will result in less duplication between configuration in code and configuration in the Dioxus.toml format

closes #1564

[ealmloff]

We need to expose const access to the cli config so that the parts of the config we need are baked into the binary at compile time. I am marking this as a draft again until that is added

[ealmloff]

That makes the base_url from Dioxus.toml work in the router and the app title from Dioxus.toml work in desktop apps automatically