Remove MUI (Material UI)

[olemartinorg]

After #2567, we now only have 23 files that import from @material-ui, including components/functions:

• ⌛ AppBar / ToolBar (New navigation #2831)
• ⛔ Collapse
• ⛔ Paper
• ⛔ Typography
• ⛔ CircularProgress
• ⌛ makeStyles / createStyles Rewriting most remaining MUI usage #2905
• ⛔ List / ListItem / ListItemIcon / ListItemText
• ⌛ useMediaQuery() Rewriting most remaining MUI usage #2905
• ⌛ Table / TableBody / TableCell / TableRow Rewriting most remaining MUI usage #2905
• ⌛ createTheme / MuiThemeProvider Rewriting most remaining MUI usage #2905

Most of these are in fairly old and untouched parts of the codebase, such as AltinnAppHeader, AltinnReceipt, AltinnSummaryTable, etc.

They should all be removed and rewritten to use other things (i.e. the design system, CSS modules, etc).

[bjosttveit]

I am making changes to AltinnAppHeader in #2831 (new navigation), so I can fix that there and avoid some conflicts