(fwRenderOgre/Text): crisp font rendering

What does this MR do?

• Improve font rendering by taking into account the dpi and rendering text at the font size.
• Update the dpi on text objects when switching to a screen with a different DPI.
• Handle vertical alignment for texts.
• Update all adaptors to use this new font rendering method.

How to test it?

• Run OgreViewer
• Load an image.
• Add some distances in the negato view.
• Go back to the 3d scenes load some landmarks (These ones for example)

Some results

Associated Issues/Merge Requests

• Issues
  • Fixes #139 (closed)
  • depends on !272 (merged)