php: integrate modphp

Build the mod_php Apache module within the main php recipe; this avoids
files in the sysroot from stepping on eachother and therefore avoids the
resulting build failure.

Changes made:
* Add an "apache2" PACKAGECONFIG, default disabled. This means that if
  you previously used the modphp recipe you now need to set
  PACKAGECONFIG for php to include "apache2".
* Bring in most patches and configure options from the modphp recipe.
* Specify ${libdir}/php5 as libdir. This avoids the PHP extensions
  directory being /usr/lib/extensions by default which is ugly.
* Tidy up some superfluous/malformed entries in FILES_${PN}-pear
* Drop obsolete PHP_MAJVER
* Replace virtclass- override with class-

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>