Feature Overview (aka. Goal Summary)
Many customers are adding a global header to their customized Backstage instance.
The header is global and should be visible on all pages and all users.

A customer should be able to enable (or disable) this feature.

The feature should be enabled by default.

Goals (aka. expected user outcomes)
When the header is enabled, the customer should be able to configure it and manage the items (icons, labels, links, input field).

For example, an administrator should be able to add a logo, and several options such as a search, notifications, users settings, and more. The administrator should be able to re-arrange the order of the icons/features and be able to position them to the left or right of the header.

Requirements (aka. Acceptance Criteria):

• As an administrator, I want to be able to enable a global header from the RHDH configuration
• As an administrator, I want the global header by enable by default, with the search, notifications, help and username as default configuration.
• As an administrator, I want to be able to add a logo and position it on the header.
• As an administrator, I want to be able to add features to the header. A feature will be an icon with or without a label and an associated action.
• As a user, when I click on a feature from the global header, I want to be redirected to another page within RHDH.
• As a user, when I click/overlay on a feature from the global header, I want to see a menu appearing. For example, a user settings icon will provide several options
• As a user, when I see a notification icon, I want to be able to see a red dot (or a number) that indicates that I have a notification message to read.
• As a user, when I click on a search icon, I want to be able to enter a text to search.

Documentation Considerations
A customer should be able to find documentation to enable/disable this feature.

If the global header is enabled, the documentation should explain how to configure it and manage the items (icons, labels, links, input field)