Allow guests users to access project releases

What does this MR do?

Currently guests are not allowed to access project releases (see https://gitlab.com/gitlab-org/gitlab-ce/issues/56402#note_153251645). This MR is changing it so guests can see releases but not repository information.

Here is what changed:

• Revert the security fix from bdee9e84.
• Do not leak repository information (tag name, commit) to guests in API responses.
• Do not include links to source code in API responses for users that do not have download_code access.
• Do not display links to source code under Assets for users that do not have download_code access.
• Show Releases in sidebar for guests.

GET :id/releases/:tag_name still do not allow guests to access releases. This is to prevent guessing tag existence.

Docs only MR here - https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/27935.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance 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

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

Closes #56838 (closed)