[META] alpha6 release issues (8.x-1.0-alpha6)

Problem/Motivation

A collection of tasks for alpha6 release.

Remaining tasks

• In Progress
• Planned
• Done
  • #2883524: Move support for responsive table column priorities to BS Base
  • #3038277: Add proper favicon.ico files for bs_base and bs_bootstrap
  • #3024839: Update to Bootstrap v4.3.1
  • #3024835: Update gulp tooklit
  • #3026851: Support multilingual SVG logos for branding block
  • #3028942: Remove height auto rule for SVG logo
  • #2969609: Radio buttons without label are hidden
  • And many others...