0030439: Visualization - extend fonts search within Font_FontMgr::FindFont() on Linux

0030439: Visualization - extend fonts search within Font_FontMgr::FindFont() on Linux

Font_FontMgr has been redesigned to:
- Store fonts in a map instead a list.
- Allow mapping multiple fonts to a single alias.
- Log informative message about usage of non-requested font (fallback).
- Register all font files within standard folders on Linux when "fonts.dir" is not found.
- Prefer specific alias ("serif") as default fallback font instead of arbitrary one in a system.

A couple of obsolete and broken font aliases have been removed;
instead, new aliases of fonts popular on Linux platform have been added.

Font_NameOfFont.hxx has been extended with more neutral aliases
"monospace", "serif", "sans-serif", "cjk" and "korean".

Font_FontAspect enumeration values have been renamed Font_FA_ -> Font_FontAspect_
with old values preserved as alias.

Font_SystemFont has been extended with a list of paths to Font_FontAspect styles,
so that entire Font Family is now defined within a single Font_SystemFont instance.
Non-resizable fonts are now ignored by Font Manager.