UI: Update style for BOR custom menu/select

Styles are mostly matching to the v-select. Mission ones need updating (most likely custom control)

Note: It would be recommended to wait until we port BOR Search to NuxtUI to avoid extensive double work

What needs improvement:
- [ ] background of the checkbox needs to be blueish when item is selected. Same as in select dropdown.
- [ ] entire checkbox needs to be clickable to allow select/deselect of the item
- [ ] verify all the shades of blue/gray are equal to the ones in select (it should mostly be done)
- [ ] when item selected
- [ ] when hovering over
- [ ] when item not selected

Start with the BOR custom menu/select and compare its styles with the v-select, while considering the note about porting BOR Search to NuxtUI first. Done means the selected checkbox background, full checkbox click target, and selected, hover, and unselected blue/gray shades match the select dropdown.

Written by the indexing model from the issue text.