Move certain attributes to WinRT.Runtime

[j0shuams]

There's a couple attributes we inject into authoring components to meet compatibility with WinRT -- "ReadOnlyArray" and "WriteOnlyArray". When there's an issue with authoring, such as the generator fails during build, then a few errors about these attributes are shown. And further they are misleading, as these attributes fail to be discovered because something else failed in the build.

To improve quality of life for devs working on features for component authoring, we should move these attributes to WinRT.Runtime. We did not do this in the past because it necessitates an assembly version change. So, we should make this change before the next release that includes an assembly version change.

https://github.com/microsoft/CsWinRT/blob/728011d7b422fa8d7e952b24ce99827d3abaa3b3/src/Authoring/WinRT.SourceGenerator/Generator.cs#L20-L32