New loading screen tips. Update for the pictures and the text.
Thread: https://wildfiregames.com/forum/topic/42341-updating-loading-screen-pictures-and-tips/
Note for the commit:
After discussion with @Langbart we should stick to the old hero pic:
https://code.wildfiregames.com/source/0ad/browse/ps/trunk/binaries/data/mods/public/art/textures/ui/loading/tips/heroes.png
Note: Some descriptions are based on the ones @wowgetoffyourcellphone uses in Delenda Est: https://github.com/JustusAvramenko/delenda_est
License: https://creativecommons.org/licenses/by-sa/3.0/
(Although by this point only some words are the same.)