Support for Security v2 API

[dlorych]

• [x] All tests passed. If this feature is not already covered by the tests, I added new tests.
• [x] All static analysis checks passed.
• [x] This pull request is on the dev branch.
• [x] I used gofmt for formatting the code before submitting the pull request.

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The functionality covers basic CRUD operations of new version of Security REST API. Still few operations are not implemented.

[github-actions[bot]]

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[dlorych]

I have read the CLA Document and I hereby sign the CLA

[dlorych]

recheck

[dlorych]

@eyalbe4 Could you check the approach taken? I have been inspired by access project service and deprecated version of security API in artifactory services. Any suggestions welcome :)

The next step is to work on other operations: add/remove user group membership, unlock user, etc.