Update to material-ui 5.x

[JL102]

Material UI renamed from 4.x to 5.x, so we will need to change out dependencies from:

    "@material-ui/core": "^4.9.9",
    "@material-ui/icons": "^4.0.1",

to:

    "@mui/material": "^5.3.0",
    "@mui/icons-material": "^5.3.0",

We cannot update from react 16.x to 17.x until updating to MUI 5.x.

Additionally, material-ui-search-bar has not been updated to MUI 5.x, so we'd need to fork it or find an appropriate replacement.

[jirihajek]

Right, but since MUI 5.x isn't compatible to 4.x, we won't rush it. That said, from what I tested, 5.x seems to go in the right direction, so we'll upgrade sometimes soon.