Add DefaultProjectTypeGuid property for C# and Visual Basic

[dsplaisted]

Fixes dotnet/sdk#522 and dotnet/cli#5131

The .NET CLI has a command to add projects to a solution. It needs to know what project type Guid to use in the solution for projects where it's not explicitly defined in the project file. This change adds a DefaultProjectTypeGuid property for C# and VB that it can use for this.

@jeffkl @rainersigwald @AndyGerlicher @jgoshi @davkean for review.

@KevinRansom @enricosada the F# targets should also add this property, I believe the F# value is {F2A71F9B-5D33-465A-A702-920D77279786}

[jeffkl]

I wonder if it should just set <ProjectTypeGuids /> instead?

[rainersigwald]

Looks good, but I notice some confusion about timeframes. dotnet/sdk#522 is set to 1.0 RTM, but @piotrpMSFT moved dotnet/cli#5131 out to 2.0.0 last week. Can we confirm that we need this for RTW (and it meets the bar)?

[jgoshi]

What about F# default project type guid?

[dsplaisted]

@jgoshi

What about F# default project type guid?

That needs to be added to the F# targets, which aren't in the MSBuild repo. I've tagged @KevinRansom and @enricosada about updating them.

[rainersigwald]

@dotnet-bot test this please

[enricosada]

@jgoshi @dsplaisted added dotnet/netcorecli-fsc#63 to track adding the f# project guid to F# target file.
I'll do that next version of FSharp.NET.Sdk

@dsplaisted @jgoshi thx for ping. If there are other stuff like that, just add me as mention, i'll followup.
If i dont reply until the closing of the issue/PR, maybe i missed the notification, so please just open an issue in https://github.com/dotnet/netcorecli-fsc repo to track it. just a reference to PR/issue is enough, i'll check it.

[AndyGerlicher]

@dsplaisted did you still want this for Update 1? Or should I close?

[jgoshi]

I think we still want this as soon as it makes sense right? So if possible to get that in to Update 1 I think that would be good? @piotrpMSFT can you confirm?

[AndyGerlicher]

@dsplaisted I'm fine with this for Update 1. Can you resolve the conflicts please? It's probably because we renamed the root folders.

[AndyGerlicher]

@dotnet-bot test Ubuntu16.04 Build for CoreCLR please

[dsplaisted]

@AndyGerlicher Is it OK to go ahead and merge this?

[jgoshi]

@dsplaisted @enricosada Do you know in which build this DefaultProjectTypeGuid is available for C#, VB, and F# projects? For the CLI in the master branch.

[enricosada]

@jgoshi for f# is defined in package reference FSharp.NET.Sdk so require a restore first.
will add that to Sdk attribute (so will work without restore) later

[jgoshi]

@enricosada Do you have an ETA for when you'll add it to the Sdk? For this work I need to it work without requiring a call to restore first.

[enricosada]

@jgoshi any time, if you need it, but it's going in next cli/vs version (sdks are bundled with cli/vs).
So need to bump the fsharp.net.sdk inside dotnet/cli