Add STM32F0 Multi-Board Examples to PlatformIO Examples Repository

[kiranj26]

Hello PlatformIO Team, 👋

I have been working on a repository called STM32 PlatformIO Playground that includes examples specifically for STM32F0 Nucleo boards (e.g., Nucleo-F030R8, Nucleo-F070RB). The examples demonstrate key peripheral configurations like GPIO, UART communication, PWM signal generation, and more, all built entirely using PlatformIO.

I’d like to contribute these examples to the official PlatformIO examples repository (e.g., platform-ststm32) if you think they could benefit the community. Currently, I’ve verified the examples with the STM32F0 family, and I’m looking to expand support to STM32F4 and other families in the future.