First community splash screens

Attached are three ready to use (and tested) full-screen splash screens:

• charging-splash.img: See-through splash (like the charging animation)
• sailfish-splash-by-explit.img: Powered by Sailfish OS splash (original picture by explit)
• lineageos-collaborators: Shows a LineageOS contributors cloud, as in the OS's Settings entry

You can see a preview of each by downloading the JPG and PNG pictures.
For flashing IMG images, read the Flashing section.