Expand the GitLab Package Registry documentation to include UI use cases and workflows

Inspired by: #29574 (comment 246349761)

Problem to solve

The current Package Registry documentation instructs users on how to connect to the GitLab registry and publish and consume packages. However, they do not discuss the user interface, what features are available, how to use the UI to gain information about packages, and what to do when something isn't working.

As we build out additional features that are outside of the publish/install workflow (package verification, automatic package creation, automatic .npmrc files, etc), we should create a new area of documentation that is more universal for all package managers in how to utilize these features.

Intended users

• Parker (Product Manager)
• Delaney (Development Team Lead)
• Sasha (Software Developer)
• Devon (DevOps Engineer)
• Sidney (Systems Administrator)
• Simone (Software Engineer in Test)

Further details

Benefits

• Help new users who are unfamiliar with the GitLab application get up to speed quickly and find help when they need it.
• By documenting how to use the UI, we will drive usage and get better feedback on how to improve the overall user experience.

Proposal

Add a new section to the Package Registry documentation that details how to use the interface to:

• Enable the feature using the UI (include screenshots)
• Navigate to and find a package
• Understand/use the available metadata
• Download files
• Delete packages
• How to tell how much storage is being used for each Package Registry
• Troubleshooting

Permissions and Security

• There are no permissions changes required for this feature.

Documentation

• Update the Package registry documentation.

What does success look like, and how can we measure that?

• Success looks like we drive additional usage of the user interface and build an improved user experience.

Links / references