Add stress-test benchmark to connect a livekit server for multiple rooms

[zesun96]

how to use: lk stress-test --rooms 5 --video-publishers 2 --audio-publishers 2 --subscribers 2 --duration 1m

log output:

Room summaries:
┌─────────┬────────┬────────────────────────┬─────────────────┬───────┐
│ Room    │ Tracks │ Bitrate                │ Total Pkt. Loss │ Error │
├─────────┼────────┼────────────────────────┼─────────────────┼───────┤
│ hhwcq_4 │ 8/8    │ 3.4mbps (1.7mbps avg)  │ 0 (0%)          │       │
│ hhwcq_2 │ 8/8    │ 4.0mbps (2.0mbps avg)  │ 0 (0%)          │       │
│ hhwcq_3 │ 8/8    │ 4.4mbps (2.2mbps avg)  │ 0 (0%)          │       │
│ hhwcq_0 │ 8/8    │ 4.7mbps (2.4mbps avg)  │ 0 (0%)          │       │
│ hhwcq_1 │ 8/8    │ 4.7mbps (2.3mbps avg)  │ 0 (0%)          │       │
│ Total   │ 40/40  │ 21.2mbps (2.1mbps avg) │ 0 (0%)          │       │
└─────────┴────────┴────────────────────────┴─────────────────┴───────┘

Output log breaking changes:

publishing audio track - yleor_pub_1   -->  publishing room plzom_3 audio track -  yleor_pub_1
publishing simulcast video track - jybls_pub_1  -->  publishing room plzom_3 simulcast video track - jybls_pub_1
publishing video track - jybls_pub_1  -->  publishing room plzom_3  video track - jybls_pub_1
Finished connecting to room, waiting 1m0s  -->  Finished connecting to room plzom_4, waiting 1m0s
subscribed to track walwt_2 TR_VCjj77AvcwDdrX video 1/2 -->  subscribed to room plzom_4 - track TR_VCjj77AvcwDdrX video 1/2