Incorporate manual modifications of font data to gen_font.py

[obrusvit]

If we run core/tools/codegen/gen_font.py script, it creates a diff in generated font definitions. This is because of manual changes done to individual glyps for better visual appearance on certain models. The changes are documented by commentary but IMHO they should be defined in the script so that manual changes to generated code are not necessary.

Changes are done to

• font_unifont_regular_16
• font_pixeloperatormono_regular_8
• font_pixeloperator_regular_8
• font_pixeloperator_bold_8
• font_ttsatoshi_demibold_18.c and font_ttsatoshi_demibold_21.c - alternative numeral glyphs used
• font_ttsatoshi_demibold_42.c - uppercase fonts completely removed to save space - they are not used anywhere at the moment