Test and document how to use HTTP basic auth in the guide

[romac]

@adizere:
The guide has no details about connecting via HTTP basic auth, but it seems some relayer operators need this and they're using the feature, so we might as well document it for future users.

Quoting @romac:

We don't have special support for HTTP authentication right now. If they are using HTTP Basic auth they can try using http://username:[email protected]:1234/ which should send the username and password through the Authorization header, but we haven't tested that.

https://github.com/informalsystems/ibc-rs/issues/2406#issue-1304490093

[romac]

Specifying the username/password in the URL does not seem to work.

To reproduce:

1. Install Caddy
2. Start gm etc. using the gm.toml below
3. Do a health check and verify that it succeeds:

$ hermes health-check

6. Put the following in a file named Caddyfile

:2022

reverse_proxy localhost:27000

basicauth /* {
  romac JDJhJDE0JEsveWtDYWRLSFNnUzFBNlY0TUo1MmUzcDVXSldVRlBNakdmWnZYeG5BY1d6eWFrYlpMWmJt
}

7. Start the reverse proxy

$ caddy run

9. Check that you can connect to the authenticated RPC endpoint of ibc-0:

$ curl -v -u "romac:test" http://localhost:2022/abci_info

11. Update rpc_addr for chain ibc-0 in ~/.hermes/config.toml to use the authenticated endpoint:

http://romac:test@localhost:2022

13. Run hermes health-check again

2022-07-28T08:15:33.115674Z  INFO ThreadId(01) [ibc-0] performing health check...
ERROR
   0: failed to spawn chain runtime
   1: relayer error
   2: RPC error to endpoint http://romac:test@localhost:2022/
   3:
   3:    0: serde parse error
   3:    1: EOF while parsing a value at line 1 column 0

---

To be continued.

[romac]

Update: I am working on adding support for basic auth to tendermint-rpc.