Fuji (Essentials)

The version number of fuji follows semver now: https://semver.org/

cherry-pick commits from fuji v4.2.1:

• docs: simplify the docs
  • use a fancy header to reflect the structure of the document.
  • add the listing of commands.
  • remove the usage of levels that deepen than h6.
  • box the code fence.
• i18n: translation fix for id_ID and zh_TW. (contributor: @yichifauzi)
• fix: ensure the commands are executes in main thread. (command_meta.delay module)
• fix: the lore of meta-data doesn't show in /fuji inspect fuji-commands gui. (fuji module)