text: Title: Refactoring: xontribs
  Body: This is metaissue for list of tasks on refactoring.
  
  Medium priority:
  * I noticed that reading the xontribs list for autoloaders takes a bit of time. It will be cool to avoid this completely e.g. when there is no xontrib module in site-packages (https://github.com/xonsh/xonsh/pull/5586).
  
  ## For community
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