Project (csproj, not sln) based switch-to-packages and -projects

[lwestfall]

Apologies if this is already being tracked elsewhere.

It's becoming more and more common to have a project that isn't under a solution. Are there any plans to support projects that have no parent solution? I just tried this on my end and got an error (see below). In looking at the dnt source it appears that the tools requiring switcher.json require a solution to exist.

Let me know if you'd like help with this (if this is a functionality you'd be interested in). I will have some time toward the end this month to contribute if desired.

System.ArgumentNullException: Value cannot be null. (Parameter 'path2')
   at System.IO.Path.Combine(String path1, String path2)
   at Dnt.Commands.Infrastructure.PathUtilities.ToAbsolutePath(String relativePath, String relativeTo) in C:\projects\dnt\src\Dnt.Commands\Infrastructure\PathUtilities.cs:line 19
   at Dnt.Commands.Packages.Switcher.ReferenceSwitcherConfiguration.get_ActualSolution() in C:\projects\dnt\src\Dnt.Commands\Packages\Switcher\ReferenceSwitcherConfiguration.cs:line 24
   at Dnt.Commands.Packages.SwitchPackagesToProjectsCommand.AddProjectsToSolutionAsync(ReferenceSwitcherConfiguration configuration, IConsoleHost host)
   at Dnt.Commands.Packages.SwitchPackagesToProjectsCommand.RunAsync(CommandLineProcessor processor, IConsoleHost host) in C:\projects\dnt\src\Dnt.Commands\Packages\SwitchPackagesToProjectsCommand.cs:line 24
   at NConsole.CommandLineProcessor.ProcessSingleAsync(String[] args, Object input)
   at NConsole.CommandLineProcessor.ProcessAsync(String[] args, Object input)
   at NConsole.CommandLineProcessor.Process(String[] args, Object input)
   at Dnt.Program.Main(String[] args) in C:\projects\dnt\src\Dnt\Program.cs:line 33