upgrade: add --fetch-before-install switch

[FnControlOption]

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Not implemented:

• Fetch source if unbottled
• --force-bottle
• --build-from-source
• Casks

[MikeMcQuaid]

I like the intent of this PR but:

• this should the default behaviour

• brew/Library/Homebrew/upgrade.rb

  Line 139 in 1802717

  fi.fetch

  should be already fetching before installation. Why is this not working as we want/expect? Perhaps it's this method that needs to be called earlier. It will also handle those that are built from source.

[FnControlOption]

Please see #11940