[Improvement] Sample command in CLI document may report error

### What would you like to be improved?

In the "cli.md" document, there are some sample commands to illustrate how to use the CLI. While if user just copy & paste them, they may get error as some name conflicts. For example, when run:

"gcli catalog update --name catalog_mysql --rename mysql"

If he already run the commands prior to this, the name "mysql" is aready been occupied. As @justinmclean suggested, this should be recorded and improved later.

### How should we improve?

The document can improved to avoid such conflict.

Start in cli.md and review the sample command sequence around `gcli catalog update --name catalog_mysql --rename mysql`. Reproduce the commands in order to confirm the naming conflict, then update the examples so a user can copy and paste them without an already-used name causing an error.

Written by the indexing model from the issue text.