New Component - Seeds Menu Component

[jaredcwhite]

This serves as a replacement for the old SideNav component in UIC, and is visually similar to the Tabs component but offers the semantics of serving a list of navigation links (aka <a> tags) rather than tabs which swap (aka show & hide) already-loaded content in realtime.

Specifications

Figma:
https://www.figma.com/file/SsYt5YsgbmOPbwr5Qk2RKB/deprecated-seeds-library?type=design&node-id=3316-10537&mode=design&t=lPbHawwcsTYWbM4j-0

zeroheight WIP:
https://zeroheight.com/5e69dd4e1/p/7110b9-menu/b/93a6d7

Previous UIC Audit of SideNav:
https://www.notion.so/exygy/SideNav-3fedafa358b1403ab6eb275414ff9deb

Notes

• The "mobile dropdown" variant was moved out of this story and into its own dedicated issue: New Component - Seeds Dropdown Component #29
• We should make sure vertical-only usage is available via a prop (rather than have it responsive or automatic in some fashion), which is a requirement for features like Mandated Accounts.
• Size, should support medium and small sized
• Nesting, vertical menus should support nesting, while horizontals menus do not
• Menu and Tabs components have only slight visual differences—is there a way to share base styles across both components?