Transforms the `Page` component into a `StoreListenerComponent`
Transforms the `Page` component into a `StoreListenerComponent`

The `Page` component had some problem to render itself in initialization.
The session was not listened so the component did not refresh when the session was initialized.

This commit do the following:

* Transform the `Page` component into a `StoreListenerComponent`
* The session is accessed by the state (which is automatically updated)

kneelnrise/vep,kneelnrise/vep,kneelnrise/vep