Test: Cover cache and cookie method for key management
Only abbreviate key after hash function was applied the second time (for superuser)
Test: Cover key management API using HookStub utility
Test: Simplify authcacheGet and authcachePost methods
Test: Add utility class for mocking/stubbing test-modules
Main: No need to remember ob_level if request is excluded anyway
API: Improve names and parameters of key-management hooks
Test: Cover authcache_add_cookie on subsequent requests
Test: Cover authcache_add_cookie
Style: Rename authcache_cookie_add to authcache_add_cookie
