v2.3.0

• added DocumentEditorPreload component for caching the editor static assets before a document is opened (ONLYOFFICE Docs 9.0 and later)
• deprecated the legacy flat props (document_fileType, document_title, documentType, editorConfig_lang, height, type, width and all events_* callbacks) in favor of the config object
• fix the editor not being reusable after unmounting the component, for example on a soft navigation
• the editor placeholder is now rendered inside a wrapper element, which is kept out of layout with display: contents
• the editor is built from the current config when it changes while api.js is still loading
• fix an editor being left behind when the component is unmounted while api.js is still loading