Implemented plugin installer

Moonlight/App/ApiClients/Modrinth/ModrinthApiHelper.cs

@@ -0,0 +1,59 @@
+using Logging.Net;
+using Newtonsoft.Json;
+using RestSharp;
+
+namespace Moonlight.App.ApiClients.Modrinth;
+
+public class ModrinthApiHelper
+{
+    private readonly RestClient Client;
+
+    public ModrinthApiHelper()
+    {
+        Client = new();
+        Client.AddDefaultParameter(
+            new HeaderParameter("User-Agent", "Moonlight-Panel/Moonlight (admin@endelon-hosting.de)")
+        );
+    }
+    
+    public async Task<T> Get<T>(string resource)
+    {
+        var request = CreateRequest(resource);
+
+        request.Method = Method.Get;
+
+        var response = await Client.ExecuteAsync(request);
+
+        if (!response.IsSuccessful)
+        {
+            if (response.StatusCode != 0)
+            {
+                throw new ModrinthException(
+                    $"An error occured: ({response.StatusCode}) {response.Content}",
+                    (int)response.StatusCode
+                );
+            }
+            else
+            {
+                throw new Exception($"An internal error occured: {response.ErrorMessage}");
+            }
+        }
+
+        return JsonConvert.DeserializeObject<T>(response.Content!)!;
+    }
+    
+    private RestRequest CreateRequest(string resource)
+    {
+        var url = "https://api.modrinth.com/v2/" + resource;
+
+        var request = new RestRequest(url)
+        {
+            Timeout = 60 * 15
+        };
+
+        request.AddHeader("Content-Type", "application/json");
+        request.AddHeader("Accept", "application/json");
+
+        return request;
+    }
+}