Adds application authorization endpoint

Implements the /Authorize endpoint to redirect users to the Tesla
authentication page. This allows users to grant the application
permission to access their Tesla account data.

Updates the public key resource to be copied on build, ensuring
it is always available at runtime.

Adds logic to validate the application registration by comparing the
public key retrieved from the Tesla API with the public key stored
locally.

Source/ProofOfConcept/ProofOfConcept.csproj

@@ -31,7 +31,7 @@
 
     <ItemGroup>
       <None Update="Resources\Signature\public-key.pem">
-        <CopyToOutputDirectory>Never</CopyToOutputDirectory>
+        <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
       </None>
     </ItemGroup>