Add horizon block with secret_key generator
Add horizon block with secret_key generator

* It will be used to encrypt cookies

Change-Id: If94cf4193473854658ca25201f4aff5f99760608
Related-Bug: 1445422

SmartInfrastructures/fuel-web-dev,huntxu/fuel-web,nebril/fuel-web,prmtl/fuel-web,prmtl/fuel-web,huntxu/fuel-web,prmtl/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,SmartInfrastructures/fuel-web-dev,huntxu/fuel-web,stackforge/fuel-web,nebril/fuel-web,huntxu/fuel-web,eayunstack/fuel-web,stackforge/fuel-web,prmtl/fuel-web,stackforge/fuel-web,nebril/fuel-web,SmartInfrastructures/fuel-web-dev,SmartInfrastructures/fuel-web-dev,nebril/fuel-web,SmartInfrastructures/fuel-web-dev,prmtl/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,nebril/fuel-web,huntxu/fuel-web