Apply for distribution of new exporters

[fengjin zeng]

Sangfor AD Exporter is a Prometheus Exporter for collecting metrics from Sangfor Application Delivery (AD) devices. If it is inconvenient to use the SNMP protocol to scrape monitoring data, you can use this exporter to obtain the running status and performance metrics of Virtual Services via API.

https://github.com/shaxiaozz/sangfor-ad-exporter