Remove sample plugin (#456)

* Delete

* Update Obsidian.sln

Obsidian.sln

@@ -9,8 +9,6 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Obsidian.Tests", "Obsidian.
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Obsidian.Nbt", "Obsidian.Nbt\Obsidian.Nbt.csproj", "{557E8CD2-EEAE-440A-B65B-D319AE900B37}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "SamplePlugin", "SamplePlugin\SamplePlugin.csproj", "{016607FE-22F8-4828-BD56-62A1E7ED220F}"
-EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Obsidian.API", "Obsidian.API\Obsidian.API.csproj", "{46AFFEB4-7478-4FC0-98E8-9B6F9EAE49BA}"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Obsidian.SourceGenerators", "Obsidian.SourceGenerators\Obsidian.SourceGenerators.csproj", "{E2E66B12-7A4B-429A-9053-8D7C731E28C1}"
@@ -40,10 +38,6 @@ Global
 		{557E8CD2-EEAE-440A-B65B-D319AE900B37}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{557E8CD2-EEAE-440A-B65B-D319AE900B37}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{557E8CD2-EEAE-440A-B65B-D319AE900B37}.Release|Any CPU.Build.0 = Release|Any CPU
-		{016607FE-22F8-4828-BD56-62A1E7ED220F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{016607FE-22F8-4828-BD56-62A1E7ED220F}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{016607FE-22F8-4828-BD56-62A1E7ED220F}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{016607FE-22F8-4828-BD56-62A1E7ED220F}.Release|Any CPU.Build.0 = Release|Any CPU
 		{46AFFEB4-7478-4FC0-98E8-9B6F9EAE49BA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{46AFFEB4-7478-4FC0-98E8-9B6F9EAE49BA}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{46AFFEB4-7478-4FC0-98E8-9B6F9EAE49BA}.Release|Any CPU.ActiveCfg = Release|Any CPU