am 2d258298: am 96764812: cherrypick Change-Id: I3c2a7ea731d2fc3c0e2372e2f1a06ed659a6539f docs: move the SIP guide into guide/network/

* commit '2d258298e2fec670908c69e38c5a3a05b1f3d0f0':
  cherrypick Change-Id: I3c2a7ea731d2fc3c0e2372e2f1a06ed659a6539f docs: move the SIP guide into guide/network/