Menubutton: dev/style updates

[sstrubberg]

• Direction There could be use cases where people want to place the menu button at the bottom. Could this add a prop to have the alignment upward? Similar to popover alignment
• Alignment How do people align the button to the right of the menu in the code?

Design Specs

carbon-design-system/carbon#14918

Acceptance Criteria

• New prop(s) for the alignment
• New prop(s) for the direction
• The actual changes to styles coming from these props (and also the new max-heights)
• new stories and controls on the stories (directionality, etc. like popover)
• VRT
• maybe unit tests