Refactor PR diff scan logic to cli-security

[attiasas]

• All tests passed. If this feature is not already covered by the tests, I added new tests.
• This pull request is on the dev branch.
• I used gofmt for formatting the code before submitting the pull request.
• Update documentation about new features / new supported technologies

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Depends on:

• Add 'Title' attribute to PR information froggit-go#148
• Add author to pull request details froggit-go#151
• Diff scan jfrog-cli-security#389

Changes:

• moving the diff logic on issues to cli-security and removing all related logic and tests
• adding platform report of PR scans

[github-actions]

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