refactored config to parse apps and backends separately
refactored config to parse apps and backends separately

although the two share much in common (they're both "components"), i
wanted to add more meta-data to apps, which didn't make much sense to
attach to backends.

dimagi/rapidsms,catalpainternational/rapidsms,lsgunth/rapidsms,lsgunth/rapidsms,ken-muturi/rapidsms,eHealthAfrica/rapidsms,unicefuganda/edtrac,rapidsms/rapidsms-core-dev,peterayeni/rapidsms,ehealthafrica-ci/rapidsms,dimagi/rapidsms-core-dev,unicefuganda/edtrac,peterayeni/rapidsms,lsgunth/rapidsms,catalpainternational/rapidsms,peterayeni/rapidsms,ehealthafrica-ci/rapidsms,caktus/rapidsms,eHealthAfrica/rapidsms,eHealthAfrica/rapidsms,dimagi/rapidsms,unicefuganda/edtrac,dimagi/rapidsms-core-dev,ken-muturi/rapidsms,catalpainternational/rapidsms,peterayeni/rapidsms,lsgunth/rapidsms,ehealthafrica-ci/rapidsms,catalpainternational/rapidsms,caktus/rapidsms,ken-muturi/rapidsms,rapidsms/rapidsms-core-dev,caktus/rapidsms