Instance level exportable security reports export file template change

Why this MR?

This MR is related to issue #213014 (closed).

What does this MR do?

This MR is introducing 2 new columns for the CSV export file, called Group Name and Project Name. These columns will be in the export file for all type of exports(instance, group and project).

It might sound that Group Name and Project Name is redundant for the project vulnerability exports but it's also good that users can see this information directly when they open the file and also using the exact same file structure for different exports simplifies the logic.

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