Breaking changes (see docs and examples for each components):
- matrix-send-event has a new API
- api.eventsManager(name, {formTemplate, displayTemplate}) to register custom events (only form to send now; coming display and edit)
- matrix-send-events to offer custom multi events type sending
- matrix-room[show-send-event,send-event-types] should work as before with the new API, but the <slot name="send"> children have changed
- removes the indexedDB in favor of previous localstorage, because indexedDB introduced async, and we did not handle that correctly