Ensure plugin is triggered for nightly builds, invalid tag name while…

[Nirupma-Verma]

… image scanning, directly consuming conjur go api than copying the code

Desired Outcome

• Ensure plugin is triggered for nightly builds. Update Jenkins file.
• Trivy scans returns invalid tag name for containers. Ensure "containerImageWithTag_ubuntu" return ubuntu container. Similar with ubi & alpine container.
• Update to directly consume conjur go api than copying the code.

Implemented Changes

• Conjur api go copied code folder internal/ removed from repo. main.go updated to consume conjur-api-go directly.

Connected Issue/Story

CyberArk internal issue ID: [CNJR-2175]

Definition of Done

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

Changelog

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

Test coverage

• 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
• A follow-up issue to update official docs has been filed here: [insert issue ID]
• This PR does not require updating any documentation

Behavior

• This PR changes product behavior and has been reviewed by a PO, or
• 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,
• These changes are part of a larger initiative with a separate security review, or
• There are no security aspects to these changes