Rename tags

I think we should rename our tag to be more explicit about our component :

• <sib-display>, <sib-router>, <sib-xxx> should be rename to <solid-display>, <solid-router>, <solid-xx> etc.
• <sib-chat> may be renamed to <sib-xmpp> since its not solid nor the only chat implementation, we could imagine a <sib-matrix> component for the matrix implementation. And we should reserve the component for a chat based on a solid server.
• The old names should be kept for retro-compatibility until v1.0, at least.