Fix some issues with generated pc files

 - Use #opt_prefix instead of #prefix or HOMEBREW_PREFIX
 - Use #version rather than hardcoded strings or @version
 - Unify pc file method naming
 - Use String#undent

Closes #18695.
iphotoexport: don't use ivars directly
pulseaudio: move to boneyard

pulseaudio no longer compiles correctly on any version of OS X.

Closes #18199.
New formula: yubikey-personalization

Closes #18692.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>