[gluon-next] Try to make devices with 8MB flash work again

[grische]

Identify which packages in the image-customazation.lua can be removed to make these devices fit again:
0669768

Inspiration can be found here:
https://github.com/ffac/site/blob/v2025.1.x/image-customization.lua#L35-L49

We will not be able to remove these packages:

• ffac-autoupdater-wifi-fallback is required for upgrades of larger mesh clouds
• ff-web-ap-timer is required for some installations