Setting Gpio alternate funcion is now an extension

[josesimoes]

Description

• Extracted this from SetDriveMode to an extension.
• Remove Alternate from GpioPinDriveMode enum.
• Requires image v0.1.0-preview460.

Motivation and Context

• Improves "separation of concerns" principle by separating the setting of the alternate function from the setting of the drive mode.
• Provides the setting of the alternate function on a extension making it formally more clear its intent.
• Fixes Gpio events do not behave as expected Home#282.

How Has This Been Tested?

• Successfully running Gpio+Events app from samples repo.

Screenshots

Types of changes

• Improvement (non-breaking change that improves a feature, code or algorithm)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Signed-off-by: José Simões jose.simoes@eclo.solutions

[nfbot]

Hi @josesimoes,

I'm nanoFramework bot.
Thank you for your contribution!

A human will be reviewing it shortly. 😉

[josesimoes]

@MikroBusNet please validate that this implementation is usable with the current use case for what it was coded for.

@AdrianSoundy please confirm that this is usable as it is for interfacing with ESP32.

[AdrianSoundy]

These changes fix in with ESP32 and make the setting of alternative functions on a gpiopin more explicit.
This function was never about drivemode.