Add USART2 support and modify system clock configuration

- Implemented USART2 initialization and interrupt handling.
- Added a function to send data to the server via USART2.
- Updated the main application to utilize USART2 for communication.
- Changed system clock configuration to use HSE and PLL for higher frequency.
- Adjusted SPI1 baud rate prescaler for improved performance.
- Enhanced LED control logic based on RFID card detection.
- Updated project configuration to reflect new USART2 settings.

Core/Src/spi.c

@@ -44,7 +44,7 @@ void MX_SPI1_Init(void)
   hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
   hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
   hspi1.Init.NSS = SPI_NSS_SOFT;
-  hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_2;
+  hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_128;
   hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
   hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
   hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;