ref(*): fix all the things

[oklopfer]

Fixes the following issues:

• Removes the Install Now button that does nothing
• requiredBy programs now show up again in their modal
• Dependencies now correctly show their provider again
• Both requiredBy and pacstallDependencies now correctly show their description in the tooltip on hover
• Split packages are now correctly parsed
• New API access vars:
  • PackageBase/packageBase: the pkgbase of the package
  • BaseIndex/baseIndex: the index of a package within a pkgbase
  • BaseTotal/baseTotal: the total number of packages built by a pkgbase
  • SourceVersion/sourceVersion: the direct pkgver var, split from epoch and pkgrel