[example] Removed left qWarning
[rpm] Enhanced description of the main package
[registry] Removed unneeded declarative interface from GriloRegistry
[qtgrilo] Remove declarative bits from the C++ library

- Implement a new GriloModel wrapper called DeclarativeGriloModel
- Removed GriloModel::get() and moved to its declarative counterpart.
- convert qmlInfo() to qWarning() in GriloMedia