The rewrite of BIND 9 build system is a large work and cannot be reasonable
split into separate merge requests.  Addition of the automake has a positive
effect on the readability and maintainability of the build system as it is more
declarative, it allows conditional and we are able to drop all of the custom
make code that BIND 9 developed over the years to overcome the deficiencies of
autoconf + custom Makefile.in files.

This squashed commit contains following changes:

- conversion (or rather fresh rewrite) of all Makefile.in files to Makefile.am
  by using automake

- the libtool is now properly integrated with automake (the way we used it
  was rather hackish as the only official way how to use libtool is via
  automake

- the dynamic module loading was rewritten from a custom patchwork to libtool's
  libltdl (which includes the patchwork to support module loading on different
  systems internally)

- conversion of the unit test executor from kyua to automake ...