Allow the caching in memory of the text files. Rather than having to read the template from file continously, we will cache them in memory.. If the file is updated (changed timestamp), then reload it
Retrieve a template (as a string String) from the cache.
Retrieve a template (as a string String) from the cache. Loads it first if not in cache yet
Returns: Parameters: - templatePath -
Throws: - Exception - if reading the template file fails.