MCBSTM32C/Project start

Project start goals:

1. Simple startup from assembler to main()
2. Switch from HSI to HSE clock (25 Mhz Crystal)
3. Initializing GPIO port E[15:8] for output - driving the leds
4. Initializing RS232 at 9600 baud
5. Initializing Interrupt controller
6. TIMER interrupt blinks the leds
7. Communicating with the UART