(fix) Umbau zu SCS

### 1.1 OpenAPI-Dokumentation implementieren
- Swagger/OpenAPI in bestehenden Ktor-Diensten integrieren
- Zentrale API-Dokumentationsseite im API-Gateway erstellen
- CI/CD-Pipeline um automatische API-Dokumentationsgenerierung erweitern
- Entwickler-Guidelines für API-Dokumentation erstellen

api-gateway/src/jvmMain/kotlin/at/mocode/gateway/routing/DocRoutes.kt

@@ -1,12 +1,9 @@
 package at.mocode.gateway.routing
 
 import at.mocode.dto.base.ApiResponse
-import io.ktor.http.*
-import io.ktor.server.application.*
 import io.ktor.server.response.*
 import io.ktor.server.routing.*
 import kotlinx.serialization.Serializable
-import java.io.File
 
 /**
  * Sets up routes for API documentation

docs/API_DOCUMENTATION_EXAMPLE.md

@@ -84,7 +84,7 @@ Following our API documentation guidelines, we would add the following to the Op
                     type: integer
                     format: int32
                     minimum: 0
-          example: 3
+                    example: "3"
             -   name: maxAge
                 in: query
                 description: Maximum age in years
@@ -93,7 +93,7 @@ Following our API documentation guidelines, we would add the following to the Op
                     type: integer
                     format: int32
                     minimum: 0
-          example: 15
+                    example: "15"
             -   name: gender
                 in: query
                 description: Horse gender