Redesign cgp_type to work as attribute macro

[soareschen]

This PR redesigns the cgp_type macro to make it an attribute macro following the same syntax as cgp_component. This is to allow for more complex CGP type components to be defined using the same macro, which may include generic parameters or super traits on the consumer trait.

The main change is as follows:

Before:

cgp_type!( Name: Display );

After:

#[cgp_type]
pub trait HasNameType {
  type Name: Display;
}

This PR also changes the implicit naming convention for the provider and component names. If no parameter is specified, cgp_type would use {Type}TypeProvider as the provider name, and {Type}TypeProviderComponent as the component name. So the above definition can also be made explicit with:

#[cgp_type {
    name: NameTypeProviderComponent,
    provider: NameTypeProvider,
}]
pub trait HasNameType {
  type Name: Display;
}