Change source code and repo license info to .NET Foundation

[Eilon]

Change all the .CS files and any other license files in the repo to be the same as ASP.NET Core.

[dougbu]

@Eilon please confirm the following assumptions:

• Should ignore the OData directory tree. It's fine to remove this tree entirely in a subsequent commit.
• Should not add copyright headers to files in the WebApiHelpPage or WebApiHelpPageVB projects. These are templates for customer projects.
• Use the following in CommonAssemblyInfo:

#if !BUILD_GENERATED_VERSION
[assembly: AssemblyCompany(".NET Foundation")]
[assembly: AssemblyCopyright("Copyright © .NET Foundation. All rights reserved.")]
#endif

Note the above does not match other Asp Net projects. The following is the norm but looks wrong given our copyright headers.

[assembly: AssemblyCompany("Microsoft Corporation.")]
[assembly: AssemblyCopyright("© Microsoft Corporation. All rights reserved.")]

[dougbu]

Also

• Should not add copyright headers to files matching *.designer.cs or *.generated.cs.

[dougbu]

1a987f8