batman-adv: Convert batman-adv.txt to reStructuredText

Converting the freeform text to parsable reStructuredText, allows the
integration in the sphinx based documentation system of the kernel. It will
therefore be accessible as hypertext under
https://www.kernel.org/doc/html/latest/

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

Documentation/networking/00-INDEX

@@ -30,8 +30,6 @@ atm.txt
 	- info on where to get ATM programs and support for Linux.
 ax25.txt
 	- info on using AX.25 and NET/ROM code for Linux
-batman-adv.txt
-	- B.A.T.M.A.N routing protocol on top of layer 2 Ethernet Frames.
 baycom.txt
 	- info on the driver for Baycom style amateur radio modems
 bonding.txt