[Improvement] Doc: `LANCE_REST_GRAVITINO_URI ` environment variable is necessary when launching Lance Rest Server by docker command

### What would you like to be improved?

`LANCE_REST_GRAVITINO_URI ` environment variable is necessary when launching Lance Rest Server by docker command. The docker inner network is separated from the host network.

It will cause the issue when used.
```
Caused by: org.apache.hc.client5.http.HttpHostConnectException: Connect to http://localhost:8090 [localhost/127.0.0.1, localhost/0:0:0:0:0:0:0:1] failed: Connection refused
at java.base/sun.nio.ch.Net.pollConnect(Native Method) ~[?:?]
at java.base/sun.nio.ch.Net.pollConnectNow(Net.java:672) ~[?:?]
at java.base/sun.nio.ch.NioSocketImpl.timedFinishConnect(NioSocketImpl.java:547) ~[?:?]
at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:602) ~[?:?]
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327) ~[?:?]
at java.base/java.net.Socket.connect(Socket.java:633) ~[?:?]
at org.apache.hc.client5.http.impl.io.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:216) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:490) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.InternalExecRuntime.connectEndpoint(InternalExecRuntime.java:164) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.InternalExecRuntime.connectEndpoint(InternalExecRuntime.java:174) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.ConnectExec.execute(ConnectExec.java:144) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.ProtocolExec.execute(ProtocolExec.java:192) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.ContentCompressionExec.execute(ContentCompressionExec.java:150) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.HttpRequestRetryExec.execute(HttpRequestRetryExec.java:113) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.RedirectExec.execute(RedirectExec.java:110) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.InternalHttpClient.doExecute(InternalHttpClient.java:183) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.hc.client5.http.impl.classic.CloseableHttpClient.execute(CloseableHttpClient.java:123) ~[httpclient5-5.4.4.jar:5.4.4]
at org.apache.gravitino.client.HTTPClient.execute(HTTPClient.java:369) ~[gravitino-client-java-1.1.0.jar:?]

```

### How should we improve?

add `LANCE_REST_GRAVITINO_URI ` environment variable in the docker command

Inspect the documented Docker launch command for the Lance Rest Server and identify where environment variables are listed. Add LANCE_REST_GRAVITINO_URI to that command, then verify the example no longer makes the container connect to localhost:8090 and that the documentation reflects the required container-network setting.

Written by the indexing model from the issue text.