Add items filter by loadout

[xoxorwr]

Fixes # .

Description of the problem being solved:

Some builds come with lots of loadouts, it causes the items menu to be bloated with items, it's hard to manage / locate a specific one / tweak.

I solved this by allowing to filter the list by loadout.

I had to shrink the delete button to make some room, what do y'all think about making the panes resizeable?

Steps taken to verify a working solution:

• I made sure no items were left out

Link to a build that showcases this PR:

Before screenshot:

After screenshot: