feature: SimpleLogger class implementation

- add SimpleLogger class
- add LogLevel enum and current_log_level which serve to show only logs with level > to it
- add trace, debug, info, warning, error functions and their abbreviate form
- add _print function which is in charge to print the message
- the message can have timestamp and type being showed before the message [<type>  ][<timestamp>]: <message>
- add the possibility to let specify a file where to save the file in append mode

plugin.cfg

@@ -0,0 +1,7 @@
+[plugin]
+
+name="Logger"
+description="A simple godot 4 logger"
+author="Arctia"
+version="0.1.0"
+script="logger.gd"