[FAB-2670] Document fabric policies creation/usage
[FAB-2670] Document fabric policies creation/usage

https://jira.hyperledger.org/browse/FAB-2670

This is a small markdown document intended to be a starting point to
understanding the policy structure of the fabric.  It is targetted for
developers who would like to roll their own configuration for a channel.

Change-Id: Ic96798e51e4e1f20ddf9c5bb7da30d6630c3bc0d
Signed-off-by: Jason Yellick <3a1724207862302656e55e6f840a9996dad69e59@us.ibm.com>

magg/fabric,blockc/fabric,ckeyer/fabric,thakkarparth007/fabric,mqshen/fabric,mqshen/fabric,hyperledger/fabric,magg/fabric,kchristidis/fabric,ckeyer/fabric,bmos299/fabric,chrisguoado/fabric,mffrench/fabric,thakkarparth007/fabric,binhn/fabric,kchristidis/fabric,ibmmark/fabric,manish-sethi/fabric-sidedb,mqshen/fabric,mffrench/fabric,rameshthoomu/fabric,binhn/fabric,ckeyer/fabric,jimthematrix/fabric,jimthematrix/fabric,chrisguoado/fabric,phariel/fabric,mffrench/fabric,mffrench/fabric,bmos299/fabric,thakkarparth007/fabric,kchristidis/fabric,king3000/fabric,king3000/fabric,xixuejia/fabric,rameshthoomu/fabric,magg/fabric,manish-sethi/fabric,tkuhrt/fabric,rameshthoomu/fabric,ibmmark/fabric,xixuejia/fabric,muralisrini/fabric,bmos299/fabric,magg/fabric,xixuejia/fabric,ibmmark/fabric,chrisguoado/fabric,mffrench/fabric,stemlending/fabric,Ryan--Yang/fabric,ckeyer/fabric,manish-sethi/fabric-sidedb,lukehuangch/fabric,tkuhrt/fabric,magg/fabric,blockc/fabric,Ryan--Yang/fabric,Ryan--Yang/fabric,lukehuangch/fabric,chrisguoado/fabric,ckeyer/fabric,cophey/fabric,manish-sethi/fabric-sidedb,cophey/fabric,chrisguoado/fabric,Ryan--Yang/fabric,chrisguoado/fabric,cophey/fabric,tkuhrt/fabric,phariel/fabric,ibmmark/fabric,tkuhrt/fabric,tkuhrt/fabric,mqshen/fabric,cophey/fabric,stemlending/fabric,binhn/fabric,muralisrini/fabric,tkuhrt/fabric,kchristidis/fabric,king3000/fabric,Ryan--Yang/fabric,ibmmark/fabric,mffrench/fabric,phariel/fabric,lukehuangch/fabric,chrisguoado/fabric,rameshthoomu/fabric,thakkarparth007/fabric,phariel/fabric,blockc/fabric,phariel/fabric,blockc/fabric,ckeyer/fabric,tkuhrt/fabric,stemlending/fabric,thakkarparth007/fabric,hyperledger/fabric,mffrench/fabric,kchristidis/fabric,cophey/fabric,bmos299/fabric,blockc/fabric,muralisrini/fabric,mqshen/fabric,rameshthoomu/fabric,kchristidis/fabric,blockc/fabric,manish-sethi/fabric-sidedb,lukehuangch/fabric,rameshthoomu/fabric,mqshen/fabric,lukehuangch/fabric,cophey/fabric,Ryan--Yang/fabric,blockc/fabric,phariel/fabric,manish-sethi/fabric-sidedb,bmos299/fabric,bmos299/fabric,kchristidis/fabric,rameshthoomu/fabric,bmos299/fabric,manish-sethi/fabric,ibmmark/fabric,king3000/fabric,stemlending/fabric,lukehuangch/fabric,king3000/fabric,magg/fabric,thakkarparth007/fabric,ibmmark/fabric,manish-sethi/fabric-sidedb,magg/fabric,mqshen/fabric,king3000/fabric,ckeyer/fabric,thakkarparth007/fabric,king3000/fabric,phariel/fabric,Ryan--Yang/fabric,lukehuangch/fabric,cophey/fabric,manish-sethi/fabric-sidedb