minor ref
fix: page guesser for twig extension
fix: asset form filter
BlockConfig entity: added javascript and stylesheet
page edit js refactor
fix: entities - mapping
avoided repetition
added nullable to block config description
assets field listener handles empty field removal
fix: page creation with already present url
fix: tree navigator - skip non routed pages
added helper method to Page entity and fix method signature
added block config editing and block editing; general refactor and variable resolver
added dummy culture/lang providers