SDK-1737 MAUI version

[echo-branch]

Reference

SDK-1737 MAUI version of the Branch SDK

Summary

This is the .NET MAUI version of the Branch SDK. Works with .NET 6+ and MAUI, it does NOT support the older Xamarin apps. Apps must migrate over to MAUI as well.

This is a rebuild of the SDK, although the code is largely the same there are significant changes to the project layout.

After review, let's do a preview release of a NuGet package while we update all docs and do additional testing.

Follow up tasks:

• Update documentation
• Build a testbed app within the SDK project

Motivation

Microsoft is moving to .NET MAUI and will no longer support Xamarin.

Type Of Change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [x] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] This change requires a documentation update

Testing Instructions

See developer notion page

cc @BranchMetrics/saas-sdk-devs for visibility.

[echo-branch]

Updated the test app, should be easier to review and verify now.

[gdeluna-branch]

Clear caches if any, but otherwise seems good.