This change removes the query syntax from the QtSmartSearchbox and all its classes. Now it only autocompletes to one
single Token, but the UI functionality for composing a query of multiple elements is still left for later use. The struct
SearchMatch is now used in the whole pipeline for passing search results back and forth.
* saving search query to undo stack with MessageSearch
* saving node and edge with name to undo stack with MessageActivateNode and MessageActivateEdge
* added FeatureController that handels distribution of MessageActivateTokens
* clearing views when refreshing or changing project
* clearing undo stack when changing project
* added StorageCache derived from StorageAccessProxy