Compatibility with Unity & Android

[AuMilliat]

Proposed modifications: Adding Microsoft.Psi.InteropAndroid, that is a reduction of Microsoft.Psi.Interop for TCPSource/Writer with a modification of dynamic to template (crash with refecerence exception on Quest).

Microsoft.Psi project modifications: PsiStore path need to be changed for Android and check the permission to write at application level. KnowSerializer instance writeable to allow the addition of ‘serializer’ and public to application level. Mutex downgrade code & Removing null check operator to be compatible with Mono & Android.

Some modifications are unnecessary (or not complete) as the first target was to use Emitters and Receivers (commit ID: 446a0fa7f3d1f4b43b2d0f763e0e879ac7f48ca5).