Implement jwks endpoint and add test for it.

This also let to some improvements/cleanups of the other tests and fixtures.

IdentityShroud.Core/DTO/JsonWebKey.cs

@@ -1,39 +0,0 @@
-using System.Text.Json.Serialization;
-
-namespace IdentityShroud.Core.Messages;
-
-// https://www.rfc-editor.org/rfc/rfc7517.html
-
-
-public class JsonWebKey
-{
-    [JsonPropertyName("kty")]
-    public string KeyType { get; set; } = "RSA";
-    
-    // Common values sig(nature) enc(ryption)
-    [JsonPropertyName("use")]
-    public string? Use { get; set; } = "sig"; // "sig" for signature, "enc" for encryption
-    
-    // Per standard this field is optional for now we will use RS256
-    [JsonPropertyName("alg")]
-    public string? Algorithm { get; set; } = "RS256";
-    
-    [JsonPropertyName("kid")]
-    public required string KeyId { get; set; }
-    
-    // RSA Public Key Components
-    [JsonPropertyName("n")]
-    public required string Modulus { get; set; }
-    
-    [JsonPropertyName("e")]
-    public required string Exponent { get; set; }
-    
-    // Optional fields
-    [JsonPropertyName("x5c")]
-    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
-    public List<string> X509CertificateChain { get; set; }
-    
-    [JsonPropertyName("x5t")]
-    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
-    public string X509CertificateThumbprint { get; set; }    
-}

IdentityShroud.Core/DTO/JsonWebKeySet.cs

@@ -1,9 +0,0 @@
-using System.Text.Json.Serialization;
-
-namespace IdentityShroud.Core.Messages;
-
-public class JsonWebKeySet
-{
-    [JsonPropertyName("keys")]
-    public List<JsonWebKey> Keys { get; set; } = new List<JsonWebKey>();
-}