Updated samples for latest Bluetooth

[AdrianSoundy]

Description

• Updated samples to support the latest version of nanoFramework.Device.Bluetooth assembly with pairing.
• Added new Central3 sample for Pairing & Authentication in Client application

Currently all sample reference local version of nanoFramework.Device.Bluetooth assembly

This will be updated once new assembly is available in nuget.

Motivation and Context

Updates for security

How Has This Been Tested?

Test locally

Types of changes

• Improvement (non-breaking change that improves a sample)
• Bug fix (fixes an issue with a current sample)
• New Sample (adds a new sample)
• Config and build (change in the configuration and build system, has no impact on code or features)

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.

[Ellerbach]

Looks good all up! Can't wait (to test all this :-)

[alberk8]

Run the Test and looks good.