adopt lib/vendor structure
remove mach.rb from homebrew-fork
rm homebrew-fork module ObserverPathnameExtension
remove numerous unused methods from homebrew-fork

Covering files:
* extend/fileutils.rb
* hardware.rb
* utils.rb
pare back homebrew-fork global.rb

first pass: more can be removed
Merge pull request #8333 from rolandwalker/strip_some_homebrew_globals

pare back homebrew-fork global.rb
Merge pull request #8332 from rolandwalker/remove_homebrew_misc_methods

remove numerous unused methods from homebrew-fork
Merge pull request #8331 from rolandwalker/remove_homebrew_observer_pathname_extension

remove homebrew-fork module ObserverPathnameExtension
Merge pull request #8329 from rolandwalker/remove_homebrew_mach

remove mach.rb from homebrew-fork
delete homebrew-fork code specific to old Rubies
Merge pull request #8328 from rolandwalker/vendor_structure

adopt lib/vendor structure
adopt okjson.rb from homebrew-fork
Merge pull request #8330 from rolandwalker/remove_homebrew_old_ruby

delete homebrew-fork code specific to old Rubies
move mktemp method into homebrew-fork resource.rb

This is the only place it is used.
No longer need to include FileUtils.
remove String class monkeypatches: start_with? and

undent_..._72
Merge pull request #8335 from rolandwalker/move_homebrew_mktemp_to_resource

move mktemp method into homebrew-fork resource.rb
Merge pull request #8334 from rolandwalker/adopt_okjson

adopt okjson.rb from homebrew-fork
remove homebrew-fork extend/fileutils.rb
Merge pull request #8336 from rolandwalker/remove_homebrew_start_with

remove `String` monkeypatches: `start_with?` and `undent_…_72`
remove homebrew-fork chuzzle method