[StyleCop] Set single, unified ruleset file for all project in the solution

[JuanAr]

Fixes #1422 and #1459

Replaces #1429

Description

In this pull request, we unified all the rules from the projects into a single ruleset file and we placed it at the solution level, we use the Directory.Build.props to set this ruleset file to all the projects in the solution

Changes made

Add BotBuilder-DotNet.ruleset file.
Remove the duplicated ruleset files from projects.

[cleemullins]

@JuanAr Proving the value of CI builds, the build is failing.

Errors are:

##[error]tests\integration\Microsoft.Bot.Builder.Integration.AspNet.WebApi.Tests\Microsoft.Bot.Builder.Integration.AspNet.WebApi.Tests.csproj(168,5): Error : This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them. For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is ......\packages\xunit.core.2.3.1\build\xunit.core.props.

##[error]tests\Microsoft.Bot.Builder.TestBot.WebApi\Microsoft.Bot.Builder.TestBot.WebApi.csproj(185,5): Error : This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them. For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is ....\packages\Microsoft.Net.Compilers.2.6.1\build\Microsoft.Net.Compilers.props.

[cleemullins]

Note: It seems the master branch is building fine. Per you email, I'm double-checking that now and have a build running. The build that was failing was an experimental build that's about pushing to Azure Artifacts.

[coveralls]

Pull Request Test Coverage Report for Build 51684

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 75.588%

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Totals
Change from base Build 51599:	0.0%
Covered Lines:	4304
Relevant Lines:	5694

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💛 - Coveralls

[cleemullins]

I don't understand why this is both here, and in each of the .csproj files. Could you elaborate?

It seems like only 1 location would be needed.

[gasper-az]

Hi @cleemullins, we update the PR for removing the double reference. Now, the StyleCop.Analyzers NuGet is only referenced in the Directory.Build.props file.