add srt usage for zlm

srt/srt.md

+## 特性
+- NACK(重传)
+- listener 支持
+- 推流只支持ts推流
+- 拉流只支持ts拉流
+- 协议实现 [参考](https://haivision.github.io/srt-rfc/draft-sharabayko-srt.html)
+- 版本支持(>=1.3.0)
+- fec与加密没有实现
+
+## 使用
+
+zlm中的srt更加streamid 来确定是推流还是拉流，来确定vhost,app,streamid(ZLM中的)
+srt中的streamid 为 `<vhost>/<app>/<streamid>?type=<push|play>& <other>=<other>`
+
+- OBS 推流地址
+
+    `srt://192.168.1.105:9000?streamid=__defaultVhost__/live/test?type=push`
+- ffmpeg 推流
+
+    `ffmpeg -re -stream_loop -1 -i test.ts -c:v copy -c:a copy -f mpegts srt://192.168.1.105:9000?streamid="__defaultVhost__/live/test?type=push"`
+- ffplay 拉流
+
+    `ffplay -i srt://192.168.1.105:9000?streamid=__defaultVhost__/live/test`
+
+- vlc 不支持,因为无法指定streamid[参考](https://github.com/Haivision/srt/issues/1015)
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srt/srt_en.md

+## feature
+- NACK support
+- listener support
+- push stream payload must ts
+- pull stream payload is ts
+- protocol impliment [reference](https://haivision.github.io/srt-rfc/draft-sharabayko-srt.html)
+- version support (>=1.3.0)
+- fec and encriyped not support 
+
+## usage 
+
+zlm get vhost,app,streamid and push or play by streamid of srt like this `<vhost>/<app>/<streamid>?type=<push|play>& <other>=<other>`
+
+- OBS push stream url
+
+    `srt://192.168.1.105:9000?streamid=__defaultVhost__/live/test?type=push`
+- ffmpeg push 
+
+    `ffmpeg -re -stream_loop -1 -i test.ts -c:v copy -c:a copy -f mpegts srt://192.168.1.105:9000?streamid="__defaultVhost__/live/test?type=push"`
+- ffplay pull 
+
+    `ffplay -i srt://192.168.1.105:9000?streamid=__defaultVhost__/live/test`
+
+- vlc not support ,because can't set stream id [reference](https://github.com/Haivision/srt/issues/1015)
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