RBAC: decoupled rules from assignments and items, implemented php manager
Fixes #499: Decoupled `Rule` from RBAC `Item`
Fixed code formattins issues
Removed test entries for MSSQL, Oracle
Removed custom Rule constructor
Splitted saveRule into insertRule and updateRule
Adjusted guide
Merge pull request #2974 from yiisoft/decouple-bizrules-from-auth-items

RBAC: decoupled rules from assignments and items, implemented php manager