gnu: Rename module 'freetype' to the more general 'fontutils'.

* gnu/packages/freetype.scm: Rename file to...
* gnu/packages/fontutils.scm: ...this.
* Makefile.am (MODULES): Rename module.
* gnu/packages/{ghostscript,grub,pdf,texlive}.scm: Rename dependency.

gnu: ghostscript: Build and install shared library and header files.

* gnu/packages/ghostscript (ghostscript): Extend build and install phases.

gnu: Add psutils.

* gnu/packages/ghostscript.scm (psutils): New variable.

gnu: Add GNU Ghostscript and its dependencies libpaper and lcms.

* gnu/packages/ghostscrip.scm: New file.
* Makefile.am (MODULES): Add it.