Follow up to Design patternfly/patternfly-design#1298
and Core patternfly/patternfly#6601

Core PR is patternfly/patternfly#7260

Notable things:

• Settings

  • Same thing for button and menu-toggle - adds .pf-v6-c-button.pf-m-settings and .pf-v6-c-menu-toggle.pf-m-settings
  • The animation is just hover/focus, so no further react work needed outside of adding the variants
  • Both take the standard <CogIcon />, which I think we should ship with the variant unless it's overridden. The icon rotates on hover, and the rotation is tuned for <CogIcon />

• Hamburger

  • Adds .pf-v6-c-button.pf-m-hamburger with .pf-m-expand and .pf-m-collapse variants that enable the arrow and set the arrow direction.
  • Requires a unique SVG with classes and things-n-stuff that differ from what react-icons can deliver currently. The current plan to get that icon in react-icons is to extend createIcon to support the things-n-stuff needed via react-icons - extend createIcon for multi-path & add hamburger icon #11858
  • We probably need some kind of opt-in for <PageToggleButton /> that enables the new fancy button & icon. Core handles all of the arrow/direction stuff for the page toggle, so no need to do anything other than drop in the hamburger button.