Interface for enabling/disabling panels

[mitar]

Currently all installed panels are displayed to the user. An interface/view where user can enable disable panels. Name, description should be given. Care should be taken, that dependencies are satisfied. So if panel has dependencies, they should be automatically selected and it should not be possible to disable them while other are selected (but some feedback should be provided why it is not possible for them to be deselected).

Additionally, currently panels provide only dependencies. We should extend this to "recommends" and "depend". Recommends are those where panel can still work, but with other panel it can do something more. And dependencies are really hard dependencies which are automatically selected in the interface. Some feedback should be provided for those panels which are recommended, when user enables the panel which recommends some other panels.

Of course, all this should be also checked on the server side, to verify selection.

And then only those panels should be displayed for the user.