Migrate to MUI 5.0 #1114
Description
Blog: https://mui.com/blog/mui-core-v5/
Guide: https://mui.com/material-ui/guides/migration-v4/
Simultaneously upgrade to Notistack 2.x https://github.com/iamhosseindhv/notistack/blob/master/CHANGELOG.md
Probably also @material-table/core 5.x
See also #752
Not super clear on what the benefits for an established codebase are. If it's just ecosystem churn then we should stay on v4 for as long as it is supported.