Loadouts Search: Add search actions dropdown

[bhollis]

This task is to add the same sort of search actions dropdown to loadouts as we have for items. Ideally also showing the count of filtered loadouts.

Some potential actions:

• Delete all matching loadouts (with a confirm dialog!)
• Add/remove notes
• Paste section
• (I don't know how we'd do "replace item")

One tricky bit is that this interacts somewhat badly with the filter pills right now. We'd probably want any bulk actions to only act on the displayed loadouts, taking into account further filtering from the pills.