Notebooks: Keyboard shortcuts

As a Notebooks user I can use keyboard shortcuts so that I can speed up my editing process

**Scenario 1: Shortcuts visible in panel menu**
Given I have selected a Notebook panel
When I'm in the panel menu
Then I can see keyboard commands right aligned next to the menu item if available

**Scenario 2: Duplicate panel**
When I use a keyboard shortcut `CMD + D`
Then the panel is duplicated

**Scenario 3: Notebooks Navigation Shortcuts (TBD)**

#### Design Notes

#### Technical Notes
Trying to align with as many existing keyboard commands as possible, but want to avoid clashing with Chrome or Safari shortcuts

Full list of shortcuts still needs to be decided on (design includes placeholder shortcuts)
Document for creating shortcuts: https://docs.google.com/spreadsheets/d/1pYjS8CJhnFoNxtNzREOoSDQrhJAYyPdOEYsXW7L3OYA/edit#gid=0

Examples of common shortcuts
https://code.visualstudio.com/shortcuts/keyboard-shortcuts-macos.pdf
https://docs.github.com/en/github/getting-started-with-github/using-github/keyboard-shortcuts
https://support.google.com/mail/answer/6594?co=GENIE.Platform%3DDesktop&hl=en#zippy=%2Cformatting-text%2Cactions