Add support for selecting auto approval mechanism
Support auto approval for clients and honor default client config
Wire up missing bean reference for TokenStore handler
Add integration tests for ApprovalStoreUserApprovalHandler
Wire up all approval handler beans and alias the desired one

This is mostly to facilitate writing integration tests to
confirm the correct functioning of the Spring provided approval
handlers with the GORM backed services provided by the plugin.
Add integration test for TokenStoreUserApprovalHandler