Standardize Ktor dependency injection on ktor-server-di

[zantvoort]

Storm already ships Ktor integration: the install(Storm) plugin with HOCON auto-configuration, repository auto-registration, coroutine-aware transactions, and storm-ktor-test. As with Spring Boot, the integration exists and works, and the 1.13.0 milestone tightens it. This issue settles the dependency injection story.

Support only the built-in DI:

Tasks:

• Bump Ktor from 3.1.2 to current 3.x
• Expose ORMTemplate and the registered repositories through ktor-server-di (new storm-ktor-di module, or folded into storm-ktor behind an optional dependency)
• Remove storm-ktor-koin
• Docs: manual wiring recipe for Koin users