vcl: Excise vcl::FontInfo class

This may sound crazy, but literally vcl::FontInfo serves no purpose
that I can see. The inheritance chain is like this:

┌────────────────────────┐
│                        │
│        vcl::Font       │
│                        │
└────────────────────────┘
^
╱ ╲
│
│
┌────────────────────────┐
│                        │
│      vcl::FontInfo     │
│                        │
└────────────────────────┘
^
╱ ╲
│
│

┌────────────────────────┐
│                        │
│       FontMetric       │
│                        │
└────────────────────────┘

vcl::FontInfo (which, incidentally, needs to be put into the vcl
namespace due to collisions with poppler!) literally does nothing
and is acting as a bridge between FontMetric and vcl::Font. Unlike
a bridge though, this bridge doesn't actually *do* anything.

So I'm removing it, which means one less class to deal with in the
vcl fonts world.

Change-Id: I32725669c9bca7fbb0846b6a062135464046e4f6
Reviewed-on: https://gerrit.libreoffice.org/21058
Reviewed-by: Chris Sherlock <chris.sherlock79@gmail.com>
Tested-by: Chris Sherlock <chris.sherlock79@gmail.com>