Enhancement Bug 4444: Centralize Code Handling Perl Dependencies

Enhancement Bug 4444: Centralize Code Handling Perl Dependencies

This patch adds two modules: C4::Installer::PerlModule and C4::Installer::PerlDependencies. The latter provides a single point
of reference for cataloging Koha Perl dependencies. The former provides an OO style interface to the dependency catalog.

The format of C4::Installer::PerlDependencies is very simply an anonymous hash of hashes. Each second level hash takes this form:

'Foo::Bar' => {
  'usage'    => 'FooBar Feature',
  'required' => '1', # 0 if optional
  'min_ver'  => '0.01',
},

New modules can be appended to C4::Installer::PerlDependencies as needed and will be picked up by every piece of code which needs
this information.

Signed-off-by: Galen Charlton <gmcharlt@gmail.com>