PWM and I2C Improvements

• New hardware PWM provider added to the GpioD plugin, see:
  • Blog: PWM Hardware Support on RPi5.
  • Documentation: I/O Examples: Pulse Width Modulation (PWM).
• Various improvements in the I2C implementation in both core and plugins, see:
  • Blog: Ongoing I2C Improvements.
• Dependency bumps in the pom file, see pull request #337.
• New BoardInfo included to detect type of Raspberry Pi board, providing a lot of info about the board, SoC, pins, etc., see:
  • Documentation: Using Board Info.
  • Example implementation and visualization on api.pi4j.com.
• Fix for "IOBase constructor do not update the fields id, name & description".
  • Issue #257: IOAlreadyExistsException when reopening Serial-connection.
  • Issue #244: Multiple SPI throws IOAlreadyExistsException.
• Several code improvements and clean-up.

Thanks to contributions by @fusetim, @taartspi, @eitch, @fdelporte.

Make sure to also read the interviews with Robert von Burg and Tom Aarts.

All changes: 2.5.1...2.6.0