Separate nuget packaging into Stable and Experimental

Author: maryamariyan

Directory.Build.props

@@ -1,7 +1,10 @@
 <Project>
   <!-- Directory.Build.props contains the common build settings for all projects in the repo. -->
 
-  <Import Project="build/BranchInfo.props" />
+  <Import Project="build/StablePackagesInfo.props" />
+  <Import Project="$(RepoRoot)build/BranchInfo.props" />
+  <Import Project="$(RepoRoot)build/BranchInfo.Stable.props" Condition="'$(MSBuildProjectName.Contains(.symbols))' == 'false' AND '$(StableProjects.Contains($(MSBuildProjectName)))' == 'true'"/>
+  <Import Project="$(RepoRoot)build/BranchInfo.Stable.props" Condition="'$(MSBuildProjectName.Contains(.symbols))' == 'true' AND '$(StableProjects.Contains($(MSBuildProjectName.Substring(0, $(MSBuildProjectName.IndexOf(.symbols))))))' == 'true'"/>
   <Import Project="build/Dependencies.props" />
 
   <PropertyGroup>

build/BranchInfo.Stable.props

@@ -0,0 +1,8 @@
+<Project>
+  <PropertyGroup>
+    <MajorVersion>0</MajorVersion>
+    <MinorVersion>12</MinorVersion>
+    <PatchVersion>0</PatchVersion>
+    <PreReleaseLabel>preview</PreReleaseLabel>
+  </PropertyGroup>
+</Project>

build/StablePackagesInfo.props

@@ -0,0 +1,14 @@
+<Project>
+    <ItemGroup>
+        <StableProject Include="Microsoft.ML"/>
+        <StableProject Include="Microsoft.ML.CpuMath"/>
+        <StableProject Include="Microsoft.ML.FastTree"/>
+        <StableProject Include="Microsoft.ML.ImageAnalytics"/>
+        <StableProject Include="Microsoft.ML.LightGbm"/>
+        <StableProject Include="Microsoft.ML.Mkl.Components"/>
+        <StableProject Include="Microsoft.ML.Mkl.Redist"/>
+    </ItemGroup>
+    <PropertyGroup>
+        <StableProjects>@(StableProject, ';')</StableProjects>
+    </PropertyGroup>
+</Project>