allow TypeScriptIntegration to write prior to the config object literal

[kuhe]

allow a typescript integration to write content outside of the runtimeConfig object literal as part of the config setup.

[kuhe]

• there are no TS package changes and yarn test passes locally

[syall]

Not in the scope of this PR, but I feel we should move away from using templates and instead migrate to writers and CodeSections.

By using DirectedCodegen, CodeInterceptors can be used. This would allow state to be accessible to the interceptors (e.g. target) and avoid adding a new integration point in TypeScriptIntegration, e.g.

public record PrepareRuntimeConfigCodeSection(LanguageTarget target) implements CodeSection {}

public final class ExamplePrepareRuntimeConfigCodeInterceptorIntegration implements TypeScriptIntegration {
    @Override
    public List<? extends CodeInterceptor<? extends CodeSection, TypeScriptWriter>> interceptors(
        TypeScriptCodegenContext codegenContext) {
        return List.of(CodeInterceptor.appender(PrepareRuntimeConfigCodeSection.class, (w, s) -> {
            // ...
        }));
    }
}