Update project configuration and snapshot files

- Changed the default project file from `plugin.project.json` to `plugin.project.json5` in `build.rs`.
- Added new project configuration files in JSON5 format for various test cases, including `default.project.json5`, `client_in_folder`, `csv_bug_145`, and others.
- Updated snapshot files to reflect changes in instance structure and properties, ensuring consistency with the new project configurations.
- Removed unnecessary script and module instances from snapshot files to streamline the testing process.

rojo-test/serve-tests/pivot_migration/default.project.json5

@@ -7,7 +7,7 @@
         "$className": "Model"
       },
       "Tool": {
-        "$path": "Tool.model.json"
+        "$path": "Tool.model.json5"
       }
     }
   }

rojo-test/serve-tests/ref_properties/default.project.json5

@@ -16,7 +16,7 @@
         }
       },
       "ModelTarget": {
-        "$path": "ModelTarget.model.json"
+        "$path": "ModelTarget.model.json5"
       },
       "FolderTarget": {
         "$path": "FolderTarget"