feat(model-server): report errors as application/problem+json

This commit modifies the v2 REST API to always report errors as
application/problem+json instances following RFC 9475. We do not declare
this as a breaking change as we never guaranteed a certain error format.

The OpenAPI specification has been extended with a default error
response for all routes to avoid having to repeat the definition many
times.

The installation of the StatusPages extension had to be moved to the
model-server Main file as this extension is now used to map instances of
the new HttpException class to suitable responses.

HttpException has been introduced due to the lack of a standard HTTP
exception hierarchy in ktor. Throwing exceptions instead of
call.respondXXX usually makes route implementations shorter and easier
to read.

Author: languitar

authorization/src/main/kotlin/org/modelix/authorization/KtorAuthUtils.kt

@@ -34,7 +34,6 @@ import io.ktor.server.auth.jwt.jwt
 import io.ktor.server.auth.parseAuthorizationHeader
 import io.ktor.server.auth.principal
 import io.ktor.server.plugins.forwardedheaders.XForwardedHeaders
-import io.ktor.server.plugins.statuspages.StatusPages
 import io.ktor.server.request.header
 import io.ktor.server.response.respond
 import io.ktor.server.response.respondText
@@ -85,28 +84,6 @@ fun Application.installAuthentication(unitTestMode: Boolean = false) {
             }
         }
     }
-    install(StatusPages) {
-        exception<Throwable> { call, cause ->
-            when (cause) {
-                is NoPermissionException -> call.respondText(
-                    text = cause.message ?: "",
-                    status = HttpStatusCode.Forbidden,
-                )
-                is NotLoggedInException -> call.respondText(
-                    text = cause.message ?: "",
-                    status = HttpStatusCode.Unauthorized,
-                )
-                else -> {
-                    val text = """
-                        |500: $cause
-                        |
-                        |${cause.stackTraceToString()}
-                    """.trimMargin()
-                    call.respondText(text = text, status = HttpStatusCode.InternalServerError)
-                }
-            }
-        }
-    }
     routing {
         authenticate(jwtAuth) {
             get("/user") {