[C#] Prepares for official Nuget release (#7496)

* Define nuget package

* C# Switch to Google.FlatBuffers namespace

* Add Source Link for nuget package

* Add Strong Name signing of Google.FlatBuffers

tests/FlatBuffers.Test/Assert.cs

@@ -19,7 +19,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
 
     public class AssertFailedException : Exception

tests/FlatBuffers.Test/ByteBufferTests.cs

@@ -17,7 +17,7 @@
 using System;
 using System.Runtime.InteropServices;
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     [FlatBuffersTestClass]
     public class ByteBufferTests

tests/FlatBuffers.Test/FlatBufferBuilderTests.cs

@@ -16,7 +16,7 @@
 
 using System;
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     [FlatBuffersTestClass]
     public class FlatBufferBuilderTests

tests/FlatBuffers.Test/FlatBuffersExampleTests.cs

@@ -21,7 +21,7 @@ using MyGame.Example;
 using optional_scalars;
 using KeywordTest;
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     [FlatBuffersTestClass]
     public class FlatBuffersExampleTests

tests/FlatBuffers.Test/FlatBuffersFuzzTests.cs

@@ -16,7 +16,7 @@
 
 using System;
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     [FlatBuffersTestClass]
     public class FlatBuffersFuzzTests

tests/FlatBuffers.Test/FlatBuffersTestClassAttribute.cs

@@ -19,7 +19,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     [AttributeUsage(AttributeTargets.Class)]
     public class FlatBuffersTestClassAttribute : Attribute

tests/FlatBuffers.Test/FlatBuffersTestMethodAttribute.cs

@@ -16,7 +16,7 @@
 
  using System;
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     [AttributeUsage(AttributeTargets.Method)]
     public class FlatBuffersTestMethodAttribute : Attribute

tests/FlatBuffers.Test/FuzzTestData.cs

@@ -16,7 +16,7 @@
 
 using System;
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     internal static class FuzzTestData
     {

tests/FlatBuffers.Test/Lcg.cs

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     /// <summary>
     /// Lcg Pseudo RNG

tests/FlatBuffers.Test/Program.cs

@@ -19,7 +19,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     static class Program
     {

tests/FlatBuffers.Test/TestTable.cs

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-namespace FlatBuffers.Test
+namespace Google.FlatBuffers.Test
 {
     /// <summary>
     /// A test Table object that gives easy access to the slot data