Add Packages::Debian::ExtractMetadataService

Context

When a .changes debian package file is uploaded, it will kick off a background job to extract metadata which is used to create a Debian package and associate other uploaded debian package files (currently "unknown" package files) with the package. This MR implements the metadata extraction service that will be used by the background job.

What does this MR do?

Service to extract metadata from Debian package files.

Item 5.3 of #5835 (comment 414103286)

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