Add mechanisms for 3PID invite expiration and AS integration

- Integration with AS and a fallback user to decline expired invites (#120)
- Rework of the AS feature to make it more independent/re-usable
- Skeleton for admin interface via bot to manage invites (#138)

src/main/java/io/kamax/mxisd/http/undertow/handler/as/v1/AsUserHandler.java

@@ -0,0 +1,46 @@
+/*
+ * mxisd - Matrix Identity Server Daemon
+ * Copyright (C) 2019 Kamax Sarl
+ *
+ * https://www.kamax.io/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.mxisd.http.undertow.handler.as.v1;
+
+import io.kamax.mxisd.as.AppSvcManager;
+import io.undertow.server.HttpServerExchange;
+
+import java.util.LinkedList;
+
+public class AsUserHandler extends ApplicationServiceHandler {
+
+    public static final String ID = "userId";
+    public static final String Path = "/_matrix/app/v1/users/{" + ID + "}";
+
+    private final AppSvcManager app;
+
+    public AsUserHandler(AppSvcManager app) {
+        this.app = app;
+    }
+
+    @Override
+    public void handleRequest(HttpServerExchange exchange) {
+        String userId = exchange.getQueryParameters().getOrDefault(ID, new LinkedList<>()).peekFirst();
+        app.withToken(getToken(exchange)).processUser(userId);
+        respondJson(exchange, "{}");
+    }
+
+}

src/main/java/io/kamax/mxisd/http/undertow/handler/status/VersionHandler.java

@@ -34,7 +34,7 @@ public class VersionHandler extends BasicHttpHandler {
 
     public VersionHandler() {
         JsonObject server = new JsonObject();
-        server.addProperty("name", "mxisd");
+        server.addProperty("name", Mxisd.Name);
         server.addProperty("version", Mxisd.Version);
 
         body = GsonUtil.getPrettyForLog(GsonUtil.makeObj("server", server));