Support for Internal LB In shared networks in advanced zone.

##### ISSUE TYPE
* Feature

##### COMPONENT NAME
* Internal LB

##### CLOUDSTACK VERSION
* CloudStack 4.17.1.0

##### CONFIGURATION
The cloudstack env is **using the Ceph RBD and local storage as cloudstack cluster primary storage** and using shared networks in advanced zone which is in https://github.com/apache/cloudstack/issues/5462

The cloudstack cluster TEST work node is eno49 and eno50 to bond0.
```
- bond0 ---> bond0.1935 ---> cloudbr0

-------> VLAN 1115
- bond0 ---> cloudbr1 -
-------> VLAN 1118

```

Now we can create the guest instance in VLAN 1115 and VLAN 1118. But in this mode I can not fount how to use the *Internal LB* service,

1. Cloud you please explan does this situation support the Internal LB?
2. If supported, How to use the *Internal LB* service?


此 issue 未指明檔案、測試或程式碼進入點。首先確定 Internal LB 預期如何在進階區域中與共用網路搭配運作；完成的標準是確定此設定是否受支援，並提供使用步驟或明確的實作範圍。

由索引模型根據 Issue 內容生成。