Blocks: visibility_roles was not correctly honoured

This is a regression introduced in fa8ec5f216.

BlocksComponent retrieves the roleId of the current user from
CroogoComponent::$roleId.  Since Blocks and Menus component runs on
on higher priority, CroogoComponent::startup() has not been executed
yet, leaving the default value being used.

Add session checks in Blocks and Menus Components and set the value to fix it.

- To properly fix this problem, `CroogoComponent::roleId()` method will be
  introduced in 1.6
- The property `CroogoComponent::$roleId` is deprecated in 1.5.x

Reported-By: Mohammad Saleh
Closes: #423