--live-reload-* command line options need documentation

I am trying to change my `live-reload-host` to `localhost` because my http port is proxied to a development url. It's unclear to find out how to do this.

```
$ ./node_modules/.bin/ember help | grep reload
--live-reload (Boolean) (Default: true)
--live-reload-host (String) Defaults to host
--live-reload-base-url (String) Defaults to baseURL
--live-reload-port (Number) (Defaults to port number within [49152...65535])
```

Needs documentation.

* `--live-reload-host` changes the **websocket host**
* `--live-reload-base-url` changes the **javascript location** relative to baseURL
* ~~`--live-reload-port` doesn't seem to work in my setup~~ overridden by `.ember-cli`

I can't seem to change the javascript location. It's always `{{rootURL}}/{{baseUrl}}/livereload.js`. But I need to change the `rootURL` _for the livereload location only._

---

```
ember-cli: 3.3.0
http_parser: 2.8.0
node: 8.12.0
v8: 6.2.414.66
uv: 1.19.2
zlib: 1.2.11
ares: 1.10.1-DEV
modules: 57
nghttp2: 1.32.0
napi: 3
openssl: 1.0.2p
icu: 60.1
unicode: 10.0
cldr: 32.0
tz: 2017c
os: linux x64
npm: 6.4.1
```