[Request] Add a libretro/external homepage value for cores

[checktext00]

Add a homepage link as an extra key/value pair (that can be presented in the RA UI on its own line) in the core info files such as

Virtual Jaguar:

# Software Information
display_name = "Atari - Jaguar (Virtual Jaguar)"
...
libretro_homepage = "https://docs.libretro.com/library/virtual_jaguar/"

And if an external homepage is present such as in this request

YabaSanshiro:

# Software Information
display_name = "Sega - Saturn (YabaSanshiro)"
...
external_homepage = "http://www.uoyabause.org/"