Add Cardreader connector documentation.

CardreaderConnector.txt

+Front View (Host connector)
+
+   PWRQ   RX    TX          GND
+     1     2     3     4     5
+     o     o     o     o     o
+        o     o     o     o
+        6     7     8     9
+       VCC  Close Close  RFU
+             Btn   Btn
+             
+For Ref.
+RS232 (PC Connector):
+
+    CD    RX    TX    DTR   GND
+     1     2     3     4     5
+     o     o     o     o     o
+        o     o     o     o
+        6     7     8     9
+       DSR   RTS   CTS   RI
+          
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