Use Objects instead of KernelObjects

Should we actually require differently built glue code for the kernel or
kernel add-ons, which should build a separate set.
Add build variable HAIKU_PORTER_CONCURRENT_JOBS

It can be set to the number of jobs specified on the haikuporter
command line. Speeds up the bootstrap build quite a bit.
Bootstrap Haiku image: add source for more required packages

* Introduce build variable HAIKU_IMAGE_ADDITIONAL_PACKAGES which can be
  set to add additional packages to the image.
* Use HAIKU_IMAGE_ADDITIONAL_PACKAGES to support specifying a list of
  additional packages via the build-package-list build profile action.
* Add htmldoc and texi2html when building the list of the packages for
  which we need source packages when building the bootstrap Haiku image.
  We don't want them on the regular image, but they are needed to build
  some packages that are on it.
Add a few standard build tools to the Development meta package
MIME DB support: avoid static initialization order issue
packagfs: fix header order
packagefs: PackageNode: fix protection issue

Only gcc 2 allows us to use a pointer to a protected method as a
template argument.
pkgman: missing include
pkgman: link against needed libstdc++
build_cross_tools: use --with-hybrid-secondary when needed