Upgrade to Bootstrap v5
We should upgrade to Bootstrap v5.
While doing this we should perhaps strip all the styles and rebuild the front-end using v5 best practices and a more utility classes approach.
See also using the fluid-container for all pages.
migration documentation: https://getbootstrap.com/docs/5.0/migration/
quite a few breaking changes
e.g.
Renamed several utilities to use logical property names instead of directional names with the addition of RTL support:
Renamed .left-* and .right-* to .start-* and .end-. Renamed .float-left and .float-right to .float-start and .float-end. Renamed .border-left and .border-right to .border-start and .border-end. Renamed .rounded-left and .rounded-right to .rounded-start and .rounded-end. Renamed .ml- and .mr-* to .ms-* and .me-. Renamed .pl- and .pr-* to .ps-* and .pe-*. Renamed .text-left and .text-right to .text-start and .text-end.
Consider doing #2755 so we can use latest components.
I think we can freely consider if we want to use Bootstrap in the future or jump to some other ship, especially if the changes seem big.