cloudapi: use Recover middleware to handle panics

recover from panics such as out-of-bounds array access & nil
pointer access, print a stack trace and return 5xx error
instead of the service crashing and relying on Execution
framework to handle crashes

internal/cloudapi/v2/v2.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v4/middleware"
 
 	"github.com/osbuild/osbuild-composer/internal/blueprint"
 	"github.com/osbuild/osbuild-composer/internal/common"
@@ -58,6 +59,8 @@ func (server *Server) Handler(path string) http.Handler {
 	e.StdLogger = server.logger
 	e.Pre(common.OperationIDMiddleware)
 
+	e.Use(middleware.Recover())
+
 	handler := apiHandlers{
 		server: server,
 	}