Add secure binaries template

What does this MR do?

Adds a new Secure template to let users download all the required resources necessary to run our Security Products, especially in Air-Gapped environments.

Later, this template will also allow downloading binaries produced in the context of &1858 (closed)

Example

The Secure-Bundle project demonstrates how to use the template (currently duplicated in my personal space).

The ruby-bundler-rails demonstrates how to use the secure-bundle above:

• This pipeline demonstrates how to use the bundle while still using the default, standard templates provided by GitLab: https://gitlab.com/gitlab-org/security-products/demos/ruby-bundler-rails/pipelines/130527785. The variables have been set in the project to use this bundle instead of the regular locations.
• This Merge Request demonstrates the same behavior, but with explicit variables in gitlab-ci.yml: gitlab-org/security-products/demos/ruby-bundler-rails!1 (closed)

Screenshots

N/A

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

refs #209258 (closed)