Merge pull request #8621 from basilfx/feature/u8g2_update

pkg/u8g2/Makefile

pkg/u8g2/Makefile.include

pkg/u8g2/README.md

pkg/u8g2/patches/0001-add-RIOT-OS-interface.patch

pkg/u8g2/patches/0001-u8g2-add-RIOT-makefiles.patch

pkg/u8g2/patches/0002-add-RIOT-interface.patch

...hange-conflicting-module-name-for-pkg-root-director.patch

pkg/u8g2/src/Makefile

pkg/u8g2/src/csrc/Makefile

pkg/u8g2/src/csrc/u8g2_riotos.c

pkg/u8g2/src/sys/sdl/common/Makefile

pkg/u8g2/src/sys/utf8/common/Makefile

tests/pkg_u8g2/main.c

tests/pkg_u8g2/tests/01-run.py