Moved TRMNL stuff to its own file

helpers.h

@@ -23,6 +23,13 @@ bool read_file_json(nlohmann::json& j, const std::string& filename, std::ostream
 // Returns - true if read and parse is successful
 bool read_stream_json(nlohmann::json& j, std::istream& in, std::ostream* log);
 
+// Writes json to supplied filename
+// j - input json
+// filename - filepath to which to write json
+// log - ostream to log human readable errors to - can be nullptr
+// Returns - true if write is successful
+bool write_file_json(const nlohmann::json& j, const std::string& filename, std::ostream* log);
+
 // JSON Extraction Helpers
 // out value is modified only if an extraction happened
 // Returns - whether an extraction happened