docs: add transports.md

License: MIT
Signed-off-by: Lars Gierth <larsg@systemli.org>

docs/transports.md

+## /ws and /wss -- websockets
+
+If you want browsers to connect to e.g. `/dns4/example.com/tcp/443/wss/ipfs/QmFoo`
+
+- [ ] An SSL cert matching the `/dns4` or `/dns6` name
+- [ ] go-ipfs listening on `/ip4/127.0.0.1/tcp/8081/ws`
+  - 8081 is just an example
+  - note that it's `/ws` here, not `/wss` -- go-ipfs can't currently do SSL, see the next point
+- [ ] nginx
+  - configured with the SSL cert
+  - listening on port 443
+  - forwarding to 127.0.0.1:8081