[security] Introduce security layer. 

It is reworked version of PoC https://github.com/Payum/PayumBundle/blob/master/Service/TokenManager.php  manager I did in 0.5 branch for symfony bundle.

This PR changes:

* [ ] `TokenManager::getTokenFromRequest` method move to its own service called `RequestVerifier::verify($request)`
* [ ] Move TokenizedDetails to security namespace and rename it to `Token`.
* [ ] Move `Payum\Util\Random` to `Payum\Security\Util\Random`.
* [ ] Add basic `RequestVerifier` for plain php setups.