Add the dependency proxy enabled/disabled setting to the instance level admin panel
Context
You can use the GitLab UI or API to turn off the group-level dependency proxy. Self-managed customers can turn off the feature at the instance level following https://docs.gitlab.com/ee/administration/packages/dependency_proxy.html#turn-off-the-dependency-proxy.
Problem to solve
The problem is that when you turn off the feature at the group level, it is still enabled for the sub-group. This means that if you want to turn off the feature and don't have Admin privileges at the instance level, you need to turn off the feature for every group and sub-group, which is quite inefficient.
In addition, for Dedicated customers, because this setting is not exposed in the UI, they don't have the ability to turn the feature off for their Dedicated instance.
Proposal
Add the instance-level setting for the dependency proxy to the instance-level admin panel, so that instance Owners can enable or disable the feature from the UI, including GitLab Dedicated customers.