refactor resources to include the bare minimum required for devices

[nilsbenson]

Based on low-mem, med-mem, high-mem roughly correlated to 64k, 128k, 1mb devices.

Will also need to take into account screen sizes for some of them as the fr235 has a relatively large screen so likes larger icons, but has low memory meaning we need to be careful how large any of the specific images are to balance it.

[arquicanedo]

I think we can close this. Most of the resource constrained devices have now small icons.