Add role memberships command

[gl-johnson]

Desired Outcome

Add support for the 'role memberships' command that previously existing in the Ruby CLI.

Implemented Changes

Add CLI functionality that allows commands with the syntax conjur role memberships -i user:someuser. Support both recursive (default) and direct membership queries (-d / --direct). Drop support for the --system flag which served no purpose.

Connected Issue/Story

CyberArk internal issue link: ONYX-23087

Definition of Done

At least 1 todo must be completed in the sections below for the PR to be merged.

Changelog

• [x] The CHANGELOG has been updated, or
• [ ] This PR does not include user-facing changes and doesn't require a CHANGELOG update

Test coverage

• [x] This PR includes new unit and integration tests to go with the code changes, or
• [ ] The changes in this PR do not require tests

Documentation

• [ ] Docs (e.g. READMEs) were updated in this PR
• [x] A follow-up issue to update official docs has been filed here: ONYX-22999
• [ ] This PR does not require updating any documentation

Behavior

• [ ] This PR changes product behavior and has been reviewed by a PO, or
• [x] These changes are part of a larger initiative that will be reviewed later, or
• [ ] No behavior was changed with this PR

Security

• [ ] Security architect has reviewed the changes in this PR,
• [x] These changes are part of a larger initiative with a separate security review, or
• [ ] There are no security aspects to these changes