[feat]: dev tools option to change image registry

[elvece]

Prerequisites

• [X] I have searched for existing issues that already suggest this feature, without success.

Describe the Feature Request

After enabling developer tools, add an option to the Embassy menu to change to the beta registry for getting beta eOS updates.

Describe the Use Case

Changing to the beta registry for getting beta eOS image updates should be an explicit, intentional action, not something enabled by a build flag. This option was removed in v0.3.1.

Developers and community beta testers can change to the beta registry by accessing a hidden menu in the UI, or via command line.

To connect to the beta marketplace for services, the beta marketplace should be added to the marketplace settings and manually switched to.

Describe Preferred Solution

No response

Describe Alternatives

No response

Anything else?

No response