- add guide to documentation and example files to repository to run coturn alongside PairDrop via Docker Compose

- enable TURN over TLS
- modified the .gitignore to ignore files with user-data
- should fix #105
- partly cherry-picked from #106

Co-authored-by: xundeenergie <xundeenergie@users.noreply.github.com>

rtc_config_example.json

@@ -2,10 +2,10 @@
   "sdpSemantics": "unified-plan",
   "iceServers": [
     {
-      "urls": "stun:stun.l.google.com:19302"
+      "urls": "stun:<DOMAIN>:3478"
     },
     {
-      "urls": "turn:example.com:3478",
+      "urls": "turns:<DOMAIN>:5349",
       "username": "username",
       "credential": "password"
     }