Migrate to antd 5

[infomiho]

Following https://ant.design/docs/react/migration-v5

• Removing less and Gulp because it's not needed anymore
• Switch to using dark theme with CSS-in-JS
• Updates various components

Left to do

• [x] Go over all the pages

[githubsaturn]

ant 4 is no longer supported. Thanks for the PR. Merging this PR as is and we'll make adjustments as follow ups.