Version 0.3.21-beta-release

Updates introduced since 0.3.20-beta-release

• eb9ddbe Upgrade front-end components - (Ni Rui) 82AE11AD1E5E8729 E
• ade4773 Upgrade backend components - (Ni Rui) 82AE11AD1E5E8729 E
• e5b5c82 Change recommended container restart condition from always to unless-stopped, which is more appreciate - (Ni Rui) 82AE11AD1E5E8729 E
• 42ee42c Replace the old vaguly.com to the current one nirui.org, as the old one no longer functions - (Ni Rui) 82AE11AD1E5E8729 E
• 9931fcd Add support to allow Presets to define admin specified console background (and tab) color (at the request of #188) - (Ni Rui) 82AE11AD1E5E8729 E