clean out unused demo and test db.json files (#1148)

* remove demo and test db JSON

* remove demo-db reference in Dockerfile

* remove preloaded-db folder in server

* cleanup package.json scripts

* remove db.json references from server

apps/server/src/setup/config.ts

@@ -5,7 +5,6 @@ export const config = {
   demoProject: 'demo project.json',
   newProject: 'new project.json',
   database: {
-    testdb: 'test-db',
     directory: 'db',
     filename: 'db.json',
   },