Restructure and fix build

[permafrost06]

• move admin page to separate package

• replace recompile, recompileOnChange scripts with wp-scripts default loaders

  • combine src/blocks/*/editor.scss files into src/editor.scss and src/blocks/*/style.scss into src/style.scss
  • combine src/blocks/*/front.js files into src/front.js

• use ultimate-blocks/ub-common instead of using library/ub-common dir

• move src/inc/components dir to separate package

• build admin page with vite instead of parcel

• move php files from src dir so that src dir can be omitted from zip

• move to psr4 classes instead of include/include_once

• get rid of parcel in pro

• move to wp-scripts plugin-zip for export script, remove pluginCompress.js