Outsource custom GUI class components to dashgui library

Move reusable GUI primitives (PanelTile, EditablePanelTile, base Tile,
ElevatedPill, SingleLineTextEdit) into the shared dashgui package and
consume them via a file: dependency. EditablePanelTile now accepts an
onError prop so error notification stays app-side.

src/components/article/boxes/ArticleViewPrice.jsx

@@ -3,7 +3,7 @@ import Box from '@mui/material/Box';
 import InputAdornment from '@mui/material/InputAdornment';
 import TextField from '@mui/material/TextField';
 import Typography from '@mui/material/Typography';
-import { EditablePanelTile } from '../../panels';
+import { EditablePanelTile } from 'dashgui/panels';
 import ArticlePriceTiersDialog from '../ArticlePriceTiersDialog';
 import ArticleUnitEditorDialog from '../ArticleUnitEditorDialog';
 import { StorageManagerContext } from '../../../api/storageManagerContext';
@@ -510,6 +510,7 @@ export default class ArticleViewPrice extends PureComponent {
         contentAlignItems="flex-start"
         value={priceValue}
         onSave={this.handleSave}
+        onError={notifyError}
         isDirty={priceDraftDirty}
         canSave={priceDraftValid}
         overlay={({ editing, draft, onChange }) => (