[META] alpha7 release issues (8.x-1.0-alpha7)

A collection of tasks for alpha7 release.

Remaining tasks

• In Progress
• Planned
• Done
  • #2998225: Visually improve views exposed forms and entity browser tabs
  • #3038262: Add support for Drush 9
• Backlog
  • #3038275: Split SASS files for better SASS opt-out control
  • #3012575: Add/port layout support for sticky navbar and absolute header options
  • #3008285: Add support for Bootstrap floating labels
  • #3008293: Remove custom jasny bootstrap offcanvas solution and use BS5 offcanvas component
  • #2844385: Default button.css file is too big
  • #2870726: Fluid type and spacing scale (opt-in in 2.1, default in 3.0)
  • #2882696: [META] Support for admin forms/pages
  • #2883247: Improve dropdown button/link support
  • #2899894: Investigate moving main form action buttons to sidebar
  • #2883831: Support for icons for mime types is missing
  • #2896011: Figure what to do with background and sizing utilities
  • #2874049: Add sub-option in gulp options to toggle deepmerge option inheritance