Revert "THRIFT-4982 Remove deprecated C# bindings from the code base"

Only compiler, test, lib and tutorial code.
diff --git a/.gitignore b/.gitignore
index d11897e..eacff5b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -184,6 +184,9 @@
 /lib/c_glib/test/testserialization
 /lib/c_glib/thriftc.pc
 /lib/c_glib/thrift_c_glib.pc
+/lib/csharp/**/bin/
+/lib/csharp/**/obj/
+/lib/csharp/src/packages
 /lib/d/test/*.pem
 /lib/d/libthriftd*.a
 /lib/d/test/async_test
@@ -231,6 +234,8 @@
 /lib/js/dist
 /lib/js/doc
 /lib/js/test/build
+/lib/netcore/**/bin
+/lib/netcore/**/obj
 /lib/netstd/**/bin
 /lib/netstd/**/obj
 /lib/nodejs/coverage
@@ -323,6 +328,8 @@
 /test/cpp/StressTestNonBlocking
 /test/cpp/TestClient
 /test/cpp/TestServer
+/test/csharp/obj
+/test/csharp/bin
 /test/dart/**/.dart_tool
 /test/dart/**/.packages
 /test/dart/**/packages
@@ -351,6 +358,9 @@
 /test/php/php_ext_dir/
 /test/py.twisted/_trial_temp/
 /test/rb/Gemfile.lock
+/test/netcore/**/bin
+/test/netcore/**/obj
+/test/netcore/Thrift
 /test/netstd/**/bin
 /test/netstd/**/obj
 /test/netstd/**/launchSettings.json
@@ -383,6 +393,10 @@
 /tutorial/cpp/TutorialServer
 /tutorial/c_glib/tutorial_client
 /tutorial/c_glib/tutorial_server
+/tutorial/csharp/CsharpServer/obj
+/tutorial/csharp/CsharpServer/bin
+/tutorial/csharp/CsharpClient/obj
+/tutorial/csharp/CsharpClient/bin
 /tutorial/d/async_client
 /tutorial/d/client
 /tutorial/d/server
@@ -407,6 +421,9 @@
 /tutorial/hs/dist/
 /tutorial/java/build/
 /tutorial/js/build/
+/tutorial/netcore/**/bin
+/tutorial/netcore/**/obj
+/tutorial/netcore/Thrift
 /tutorial/netstd/**/bin
 /tutorial/netstd/**/obj
 /tutorial/netstd/Interfaces