feat(samples): add CLI sample using picocli (issue #22)

[saksham869]

Adds a CLI sample for hiero-enterprise-java using picocli, as requested in #22.

What's included

• create-account — creates a new Hiero account
• create-topic — creates a topic with optional memo
• send-message — submits a message to an existing topic

Structure

Follows the same pattern as hiero-enterprise-spring-sample and
hiero-enterprise-microprofile-sample, built on hiero-enterprise-base
with no framework dependency.

Closes #22

@hendrikebbers

[saksham869]

Hi @hendrikebbers — I've submitted PR #130 adding the CLI sample using picocli:
#130
Happy to make any changes you'd like!

[amkr6207]

Thanks for working on this.

I think PR-3 should wait for maintainer feedback on PR-1 (#127) and PR-2 (#126), so the CLI sample follows the same agreed direction.

A couple of concerns here:

1. The CLI flows are not aligned with the flow direction being established in PR-1 and PR-2.
2. This PR also includes an unrelated MicroProfile change, so it is not scoped only to the CLI sample.

It may be better to revisit PR-3 after feedback on the first two PRs.

@Ndacyayisenga-droid, @manishdait, @hendrikebbers PTAL. Thanks!