Support specifying path to Nuget.Config for NuGet settings on VS

[vsfeedback]

In a large, multi-solution environment, managing Nuget sources can be a problem, especially when repeated change is required in those sources. By default, when no solution is open, you edit your machine's nuget.config and when you edit your local folder's nuget.config. This can lead to dozens of nuget.config files existing that need to be found and updated when a change occurs.

it would be great to be able to specify a file path for the nuget.config to use for a solution.

It would be better if we could specify a source control path to use for nuget.config for the solution.

This issue has been moved from https://developercommunity.visualstudio.com/content/idea/384979/support-specifying-path-for-nugetconfig.html
VSTS ticketId: 731466
These are the original issue comments:

Fiona Niu[MSFT] on 11/18/2018, 08:22 PM (44 hours ago):

Thank you for taking the time to provide your suggestion. We will do some preliminary checks to make sure we can proceed further. You will hear from us in about a week on our next steps.

[anangaur]

Related epic issue: #7284

[nkolev92]

If a NuGet.Config is placed next to a solution file it already is treated as a solution level config.

Furthermore if you set the clear tag for all the elements you are effectively limiting the configuration to just that single file.
See https://github.com/NuGet/NuGet.Client/blob/dev/NuGet.Config for example.

Basically, you can already achieve most of this ask with the current state of the tooling.
The limitation is that you cannot edit that specific config from the VS UI.

I think this is something that should be taken into consideration when tackling #1820, which talks about the overall config experience rather than 1 specific scenario.

tldr;
I think we can/should dupe this out to #1820 and add the feedback there.

[rrelyea]

Duping out to #1820