Restrict GitLab Employee Badge to only human users

What does this MR do?

With the introduction of GitLab Employee Badge, it was observed that the badge applies to all types of users including bots, service users that have email domain as gitlab.com.

This MR adds a restriction to allow the GitLab Employee Badge to only human users.

Also, currently the gitlab_employee? and organization methods are in the CE codebase. Since these methods are applicable only for GitLab.com environment (which runs on EE), this MR also moves existing code into the EE codebase.

Tests:

Workflow	GitLab.com	CE
Issue list & show
Merge Request list & show
Epic list		NA
Organization field in User Profile

Mentions #213901 (closed)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team