Allow users to not transcode live streaming video

@victorges is already working on this.

Since Dec 19, 2022.

From our documentation:

> If you do not define transcoding rendition profiles when creating the stream, a default set of profiles will be used with 720p, 480p, 360p and 240p renditions. To disable transcoding for your stream you have to explicitly set an empty array of profiles in your stream object. Beware that in that setup, your playback video will have the attributes of the source stream only and will not take advantage of adaptive bitrate streaming, likely buffering on playback.

However, if a user creates a stream with an empty array

```
curl -X POST \
-H 'content-type: application/json' \
-H 'authorization: Bearer [api_key]' \
-d '{
"name": "test_stream",
"profiles": []
}' \
https://livepeer.studio/api/stream
```

They'll get a response without profiles

```
{
"lastSeen":0,
"isActive":false,
"record":false,
"suspended":false,
"sourceSegments":0,
"transcodedSegments":0,
"sourceSegmentsDuration":0,
"transcodedSegmentsDuration":0,
"sourceBytes":0,
"transcodedBytes":0,
"profiles":[

],
"name":"test_stream",
"kind":"stream",
"userId":"c7237bc3-8d7d-4ee6-b908-c3db50bb034b",
"renditions":{

},
"id":"3363ee17-c7c2-4d6b-90b4-dec84ba7fe56",
"createdAt":1664364428131,
"streamKey":"3363-unuh-tzrm-zp6j",
"playbackId":"3363pue2y8n66mhi",
"createdByTokenName":"test",
"multistream":{
"targets":[

]
}
}
```

But the stream is still transcoded:
```
[ERICs-MacBook-Pro-2][ericxtang]-> curl -L https://livepeercdn.com/hls/3363pue2y8n66mhi/index.m3u8
#EXTM3U
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-STREAM-INF:CODECS="avc1.640028,mp4a.40.2",RESOLUTION=1920x1080,FRAME-RATE=30,BANDWIDTH=1248125,AVERAGE-BANDWIDTH=1056106
1_0/index.m3u8?mTrack=1&iMsn=1&sessId=4206290441
#EXT-X-STREAM-INF:CODECS="avc1.4d401f,mp4a.40.2",RESOLUTION=1280x720,FRAME-RATE=30,BANDWIDTH=1118738,AVERAGE-BANDWIDTH=946625
2_0/index.m3u8?mTrack=1&iMsn=1&sessId=4206290441
#EXT-X-STREAM-INF:CODECS="avc1.4d401e,mp4a.40.2",RESOLUTION=640x360,FRAME-RATE=30,BANDWIDTH=552791,AVERAGE-BANDWIDTH=467746
3_0/index.m3u8?mTrack=1&iMsn=1&sessId=4206290441
#EXT-X-STREAM-INF:CODECS="avc1.4d4015,mp4a.40.2",RESOLUTION=426x240,FRAME-RATE=30,BANDWIDTH=802391,AVERAGE-BANDWIDTH=678946
4_0/index.m3u8?mTrack=1&iMsn=1&sessId=4206290441
```