Remove SponsorLink code and bring back analyzers

The existing analyzers are super helpful for authoring projects. When we removed the CodeAnalysis project entirely to remove SponsorLink, we also lost all authoring analyzers :(

Fixes #462

Author: kzu

src/CodeAnalysis/CodeAnalysis.csproj

@@ -14,7 +14,6 @@
     <PackageReference Include="ThisAssembly.AssemblyInfo" Version="1.4.1" PrivateAssets="all" />
     <PackageReference Include="ThisAssembly.Strings" Version="1.4.1" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.0.1" Pack="false" />
-    <PackageReference Include="Devlooped.SponsorLink" Version="0.11.0" />
   </ItemGroup>
 
   <ItemGroup>

src/CodeAnalysis/NuGetizer.CodeAnalysis.targets

@@ -27,8 +27,4 @@
     </ItemGroup>
   </Target>
 
-  <ItemGroup Label="SponsorLink">
-    <SponsorablePackageId Include="NuGetizer" />
-  </ItemGroup>
-
 </Project>

src/CodeAnalysis/SponsorLinker.cs

@@ -42,7 +42,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <!--<ProjectReference Include="..\CodeAnalysis\CodeAnalysis.csproj" ReferenceOutputAssembly="false" />-->
+    <ProjectReference Include="..\CodeAnalysis\CodeAnalysis.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <ItemGroup>