🐛 #1426 修复多公众号管理的两个问题

1、允许动态更新公众号的配置，原有逻辑：更新配置时会报“该公众号标识已存在，请更换其他标识！”；
2、多公众号的消息路由，原有逻辑问题：handler里WxMpConfigStorageHolder不能获取到appid，意味着用的wxmpservice不对，只会走默认的，已测试存在该问题

Author: silloy

weixin-java-mp/src/main/java/me/chanjar/weixin/mp/api/WxMpMessageRouter.java

@@ -152,6 +152,13 @@ public WxMpXmlOutMessage route(final WxMpXmlMessage wxMessage, final Map<String,
     return route(wxMessage, context, null);
   }
 
+  /**
+   * 处理不同appid微信消息
+   */
+  public WxMpXmlOutMessage route(final String appid, final WxMpXmlMessage wxMessage, final Map<String, Object> context) {
+    return route(wxMessage, context, this.wxMpService.switchoverTo(appid));
+  }
+
   /**
    * 处理微信消息.
    */
@@ -228,6 +235,10 @@ public WxMpXmlOutMessage route(final WxMpXmlMessage wxMessage) {
     return this.route(wxMessage, new HashMap<String, Object>(2));
   }
 
+  public WxMpXmlOutMessage route(String appid, final WxMpXmlMessage wxMessage) {
+    return this.route(appid, wxMessage, new HashMap<String, Object>(2));
+  }
+
   private boolean isMsgDuplicated(WxMpXmlMessage wxMessage) {
     StringBuilder messageId = new StringBuilder();
     if (wxMessage.getMsgId() == null) {

weixin-java-mp/src/main/java/me/chanjar/weixin/mp/api/impl/BaseWxMpServiceImpl.java

@@ -399,9 +399,6 @@ public void setMultiConfigStorages(Map<String, WxMpConfigStorage> configStorages
   @Override
   public void addConfigStorage(String mpId, WxMpConfigStorage configStorages) {
     synchronized (this) {
-      if (this.configStorageMap.containsKey(mpId)) {
-        throw new RuntimeException("该公众号标识已存在，请更换其他标识！");
-      }
       this.configStorageMap.put(mpId, configStorages);
     }
   }