[Improvement] Display index infromation for tables in the Gravitino CLI

[justinmclean]

What would you like to be improved?

Have a command to display index information for Tables.

How should we improve?

This can be done by:

• Adding a new CLI command to display index information by calling index on the Table object.
• Adding a new command option --index
• Adding the command to GravitinoCommandLine
• Updating user documentation

[lsyulong]

I want to try it, but I don't know how to modify it. Can you help me

[justinmclean]

Thanks for offering to help.

To get started on this, have a look at the commands in clients/cli/src/main/java/org/apache/gravitino/cli/commands/, ListColumns.java would be a good one to copy, create a new command called sayListIndexes.java. It would call the index() method from loadTable() to get information about the table's indexes, and print out the name and type of each index.
Next, add an index option to GravitinnoOptions.java and modify handleTableCommand in GravitionoCommandLine.java to create the new command when passed the new option and the details command. Compile and test the command with the Gravitino playground. I would expect the command to be like this:
gcli table details --metalake metalake_demo --name catalog_postgres.hr.salaries --index
Finally, update the documentation in docs/cli.md adding the command to it.

[justinmclean]

@lsyulong do you want to work on this?