Removing unused references and updating the ClientSemVer to 0.2.0-preview

[jmprieur]

Improving the project files.

• Removing from Microsoft.Identity.Web/MicrosoftIdentity.Web.UI the references to Microsoft.AspNetCore.Authentication.Cookies and Microsoft.Extensions.DependencyInjection which are already transitively added by ASP.NET Core.
• Updating the ClientSemVer to 0.2.0-preview in MIcrosoft.Identity.Web and Microsoft.Identity.Web.UI
• Using the same mechanism in AspNetCoreMicrosoftIdentityWebProjectTemplates.csproj as in Microsoft.Identity.Web.csproj and MicrosoftIdentity.Web.UI.csproj to align the versions;