Merge | SqlBulkCopy (#3405)

* Make merge file for SqlBulkCopy - wowee, these files are pretty close together already!

* Remove old SqlBulkCopy files and point projects to common project one

* Addressing the easy differences

* Fix broken documentation links

* Stub out more methods/classes to eliminate most of the errors in SqlBulkCopy

* Resolve the rest of the conflicts

* Fix mistake in conflict resolution

* Addressing PR feedback

Author: benrr101

src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj

@@ -522,6 +522,9 @@
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\SqlBuffer.cs">
       <Link>Microsoft\Data\SqlClient\SqlBuffer.cs</Link>
     </Compile>
+    <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\SqlBulkCopy.cs">
+      <Link>Microsoft\Data\SqlClient\SqlBulkCopy.cs</Link>
+    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\SqlBulkCopyColumnMapping.cs">
       <Link>Microsoft\Data\SqlClient\SqlBulkCopyColumnMapping.cs</Link>
     </Compile>
@@ -803,7 +806,6 @@
     </Compile>
 
     <Compile Include="Microsoft\Data\SqlClient\SqlAppContextSwitchManager.NetCoreApp.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\SqlBulkCopy.cs" />
     <Compile Include="Microsoft\Data\SqlClient\SqlConnectionFactory.AssemblyLoadContext.cs" />
     <Compile Include="Microsoft\Data\SqlClient\SqlCommand.cs" />
     <Compile Include="Microsoft\Data\SqlClient\SqlConnection.cs" />