Add keyboard shortcuts for save, help, etc

[ghost]

Please describe the feature

As a user of Urdr, I want to be able to save what I have been doing using a keyboard shortcut so that I do not have to find the save button via tabbing 99 times to press save.

Detailed description

Add keyboard shortcuts either with aria-keyshortcuts or html accesskey. Check (https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-keyshortcuts) and (https://www.w3.org/TR/wai-aria-practices-1.2/#kbd_shortcuts) for guidance. (https://www.w3.org/WAI/ARIA/apg/practices/keyboard-interface/#kbd_shortcuts)

Perhaps something like Alt+S for save? A shortcut must not be a single key (https://www.w3.org/WAI/WCAG21/quickref/?currentsidebar=%23col_overview&showtechniques=214#character-key-shortcuts).

Additional context