* fix a patch files accept multiple patches
* fix comments and variable name
* add error handling when using not allowed multiple strategic-merge patches
* fix error message of Multiple Strategic-Merge Patch file
* refactor transformStrategicMerge()
* add TODO comment and test for Multiple JSON patch Yaml documents are not allowed
* refactoring PatchTransformer
* add multiple patch test for PatchTransformer package
* improve error message to PatchTransformer
* refactor const and error message check
* fix some error messages