Added classes to manage GPIO timer. It's not properly working

...32gg/efm32gg332f1024_wandstem/interfaces-impl/cstimer.cpp

...g/efm32gg332f1024_wandstem/interfaces-impl/gpio_timer.cpp

...2gg/efm32gg332f1024_wandstem/interfaces-impl/gpio_timer.h

...4_wandstem/interfaces-impl/high_resolution_timer_base.cpp

...024_wandstem/interfaces-impl/high_resolution_timer_base.h

miosix/interfaces/cstimer.h