Add a search feature

[iamlogand]

Add a search bar or icon somewhere. Clicking it should open a search dialog box containing a search bar and the search results (taking inspiration from the search features on sites like https://tailwindcss.com and https://mui.com/).

The searchable items can be Factions, Senators, and Terms.

The search dialog should contain a search bar at the top, then, beneath that, a list of all Factions, Senators, and Terms. These can all be represented by text for now. Typing something into the search bar should narrow the results, with the list being updated immediately upon any change to the search text, character by character. The top item should be initially selected, but pressing the up or down arrow key can allow moving the selection to other items. Pressing enter or clicking an item should close the search dialog and open the detail section for the selected item.

[iamlogand]

Closing because this was delivered by #449 and #451.