Handle async index db initialization errors, fixes tutadb 1805

Errors while initializing the DBFacade are now handled inside DBFacade and re thrown as DBError to prevent uncaught errors.

Errors from the event queue are also not reported as uncaught error by EntityClient anymore as they are thrown anyway.

src/api/worker/EventBusClient.ts

@@ -558,7 +558,6 @@ export class EventBusClient {
 			await this.processEventBatch(modification)
 		} catch (e) {
 			console.log("ws error while processing event batches", e)
-			this.listener.onError(e)
 			throw e
 		}