Github action building

[nimrof]

I have no idea if the compiled firmware is any good, so check that thorough

• Changed fpos_t -> fpos_tt as the old naming probably did not work as compiler/std-lib has changed?
• Added u8glib to makefile, did not find out how to compile it any other way from the makefile
• Downloaded missing font during build, maybe not as it is copyrighted?
• updated the .gitignore to match files from avr-gcc

for built firmware and build logs see:
https://github.com/nimrof/PancakeBot-firmware/actions/runs/5649377211