VS: Add support for per-config C# sources

Fixes: #22108
44 jobs for !6055 with vs-config-specific-csproj in 49 minutes and 26 seconds (queued for 2 seconds)
detached
Status Job ID Name Coverage
  Build
manual #5758662
linux docker build cmake manual
build:centos6-x86_64
passed #5758659
linux docker build cmake
build:debian10-iwyu

00:02:07

manual #5758663
linux-3.17 linux docker build cmake manual
build:fedora33-ninja
passed #5758661
linux-3.17 linux docker build cmake
build:fedora33-sphinx

00:02:10

passed #5758660
linux-3.17 linux docker build cmake
build:fedora33-tidy

00:05:44

manual #5758665
nonconcurrent xcode-12.4 shell macos cmake manual
build:macos-x86_64-makefiles
manual #5758664
nonconcurrent xcode-12.4 shell macos cmake manual
build:macos-x86_64-ninja
passed #5758666
nonconcurrent msvc-19.28-16.9 vs2019 shell windows cmake manual
build:windows-vs2019-x64-ninja

00:02:52

 
  Test
created #5758667
x11 linux-3.17 linux docker cmake
test:fedora33-ninja
created #5758669
nonconcurrent xcode-12.4 shell macos cmake
test:macos-x86_64-makefiles
created #5758668
nonconcurrent xcode-12.4 shell macos cmake
test:macos-x86_64-ninja
passed #5758670
nonconcurrent msvc-19.28-16.9 vs2019 shell windows cmake
test:windows-vs2019-x64-ninja

00:13:41

 
  Test Ext
created #5758673
linux docker cuda-rt cmake
test:cuda10.2-nvidia
created #5758671
linux-3.17 linux docker build cmake
test:debian10-ninja
created #5758672
linux-3.17 linux docker build cmake
test:fedora33-makefiles
created #5758674
linux-3.17 linux docker build cmake
test:fedora33-ninja-multi
created #5758675
concurrent xcode-12.4 shell macos cmake
test:macos-x86_64-xcode
passed #5758676
concurrent msvc-19.28-16.9 vs2019 shell windows cmake
test:windows-vs2019-x64

00:27:07

 
  External
passed cdash

passed ghostflow-check-master

passed ghostflow-stager

passed cdash

passed cdash

passed cdash

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager