Home: Add ability to ignore failed sources in VS

[nkolev92]

Issue motivated by https://developercommunity.visualstudio.com/content/problem/78218/nuget-systemaggregateexception.html

We currently have a gap where in NuGet.exe you can ignore failed sources while in Visual Studio you can't.
This might be a good candidate to align among the clients.

In addition, this feature as currently working is not factored in the no-op which means this is a potential inconsistency, although it's a minor concern.

Spec - https://github.com/NuGet/Home/wiki/Package-Sources-Diagnostics

[rrelyea]

@nkolev92 - understand the title. Let's discuss what led you to think this should be fixed in 4.4, and discuss the feature we designed about a year ago that relates. Please grab me in person sometime early this week.

[nkolev92]

@rrelyea
Updated the body of the issue.
During the feedback triaging few weeks back, I just added all issues to 4.4 in order to make sure we triage all of them appropriately before 4.4

[anangaur]

Related issue: https://github.com/NuGet/Home/issues/5373

Let us discuss the right fix before implementation.

[emgarten]

Related: https://github.com/NuGet/Home/issues/3058

[AndreyAkinshin]

Any updates?

[rrelyea]

This remains in our backlog, but not imminent.