Redesign for actions in dashboards header (OOTB dashboards vs. custom dashboards)
### Description
- move "Star dashboard", "Add metric" and "Edit dashboard" inside of the actions menu
- conditionally show and/or display a disabled (i.e. greyed out) state for some items in the actions menu based on the current dashboard being OOTB or custom
- replace the current icon of the actions menu with a hamburger icon
#### Action menu item states
These are the states of the actions menu items based on whether the current dashboard is OOTB or custom.
| Item | Rendered | Disabled | Observations |
| --- | --- | --- | --- |
| Add metric | OOTB | n/a | |
| Edit dashboard YAML | OOTB/Custom| OOTB | This is rendered but disabled in OOTB in order to entice users to create a new dashboard and edit it |
| Duplicate current dashboard | OOTB | n/a | In the future the Custom dashboards will also be duplicatable |
| Star dashboard | OOTB/Custom | n/a | Text toggles between *Star dashboard / Unstar dashboard* |
| Create new dashboard | OOTB/Custom | n/a | |
#### Screenshot

#### Videos
| OOTB dashboard | Custom dashboard |
| --- | --- |
| | |
This an Implementation issue for https://gitlab.com/gitlab-org/gitlab/-/issues/220931. This issue is critical to allow us to implement [add data to a custom dashboard](https://gitlab.com/gitlab-org/gitlab/-/issues/218660), if designs need to be prioritized we should implement the custom dashboard actions first and OOTB dashboard second.
### Proposal
- The "Add panel" action MVC will be implemented in custom dashboards in 13.3.
- Actions that are unavailable in the Default dashboard should be disabled and have a tooltip on hover.
:arrow_right: [Designs on Figma](https://www.figma.com/file/2AYn03HSXKwUdHfnoovjXM/OOTB-vs.-Custom-dashboard-controls?node-id=53%3A629) :arrow_left:
issue