tools: boot: hack together the start of a new development menu

[kevans]

Summary

For now, let's just preload all of the graphics we installed and offer
carousels to cycle through all of them. In the future, we may add more
and offer some linting of each brand/logo.

This just requires a few things to be exported from the drawer, in
particular the ability to add brands and logos, and an iterator to
collect all of the brands/logos we have (which include some builtins).