feat: Improve PolarisAdminTool default output

[MonkeyCanCode]

What changes were proposed in this pull request?

Polaris admin tool was default to show a brief msg which then ask user to use argument help to get more info (which is a kinds no-ops and force user to rerun the command with additional arguments in order to learn more) such as following:

$ java -jar runtime/admin/build/quarkus-app/quarkus-run.jar
Polaris administration & maintenance tool.
Use the 'help' command.

With the change from this PR, I am purposing we should default to help along with original tool message line such as following:

$ java -jar runtime/admin/build/quarkus-app/quarkus-run.jar
Polaris administration & maintenance tool.

Usage: polaris-admin-tool.jar [-hV] [COMMAND]
Polaris Admin Tool
  -h, --help      Show this help message and exit.
  -V, --version   Print version information and exit.
Commands:
  help       Display help information about the specified command.
  bootstrap  Bootstraps realms and root principal credentials.
  purge      Purge realms and all associated entities.

Why are the changes needed?

Does this PR introduce any user-facing change?

IMO, this is provide better user experience and it doesn't make much sense to ask user to type same command and an extra help argument to learn more about the tool.

How was this patch tested?

N/A

CHANGELOG.md

N/A

[singhpk234]

SGTM ! thanks @MonkeyCanCode

[dimas-b]

+1 to the general direction of this improvement. Thanks for working on this @MonkeyCanCode ! Also +1 to @snazy 's comments :)

[snazy]

LGTM!
+1