Moved main.py contents to documentation as a simple example.

@@ -0,0 +28,4 @@
+    asyncio.run(main())
+    '''
+    def __init__(self):
+        self.reader = MFRC522(spi_id=1, sck=10, miso=12, mosi=11, cs=13, rst=9, tocard_retries=10)

@@ -0,0 +40,4 @@
+        '''
+        return '0x' + ''.join(f'{i:02x}' for i in uid)
+
+    async def _reader_poll_task(self, poll_interval_ms: int = 50) -> list: