expand description of IPSec configuration format and encryption options
expand description of IPSec configuration format and encryption options

Signed-off-by: Andrey Devyatkin <e747c6fb244ee93cf2dfe222cf50b904f9eaef0a@fivexl.io>

cilium/cilium,tklauser/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,tgraf/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,tklauser/cilium