Break `codegen-server`'s dependency on `codegen-client` (#2105)

* Move the allow lints customization into `codegen-core`
* Move the crate version customization into `codegen-core`
* Move "pub use" extra into `codegen-core`
* Move `EventStreamSymbolProvider` into `codegen-core`
* Move the streaming shape providers into `codegen-core`
* Refactor event stream marshall/unmarshall tests
* Break `codegen-server` dependency on `codegen-client`
* Split up `EventStreamTestTools`
* Move codegen context creation in event stream tests
* Restructure tests so that #1442 is easier to resolve in the future
* Add client/server prefixes to test classes
* Improve TODO comments in server event stream tests
* Use correct builders for `ServerEventStreamMarshallerGeneratorTest`
* Remove test cases for protocols that don't support event streams