Use the plugin builder website instead of docker to fetch plugins (#4285)

BTCPayServer/Plugins/PluginBuilderClient.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace BTCPayServer.Plugins
+{
+    public class PublishedVersion
+    {
+        public string ProjectSlug { get; set; }
+        public long BuildId { get; set; }
+        public JObject BuildInfo { get; set; }
+        public JObject ManifestInfo { get; set; }
+    }
+    public class PluginBuilderClient
+    {
+        HttpClient httpClient;
+        public HttpClient HttpClient => httpClient;
+        public PluginBuilderClient(HttpClient httpClient)
+        {
+            this.httpClient = httpClient;
+        }
+        static JsonSerializerSettings serializerSettings = new JsonSerializerSettings() { ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver() };
+        public async Task<PublishedVersion[]> GetPublishedVersions(string btcpayVersion, bool includePreRelease)
+        {
+            var result = await httpClient.GetStringAsync($"api/v1/plugins?btcpayVersion={btcpayVersion}&includePreRelease={includePreRelease}");
+            return JsonConvert.DeserializeObject<PublishedVersion[]>(result, serializerSettings) ?? throw new InvalidOperationException();
+        }
+    }
+}