Move Key Store configuration into separate tab inside federation view

Currently Key Stores are configured under "Digital Certificates" configuration tab on federation overview page. I suggest we move it to separate tab under federation view – similarly to how IDP and SP are managed now.

1. Federation page will contain top tabs for IDP, SP and Key Store
2. Under Key Store tab I can add Key Store (pretty much the same as for IDP)
3. Detail Area will have tabs for attributes and Alias / Host config (again pretty much the same as attribute / SAML Handlers under IDP)

This will make the configuration much clearer.