cmake: Add cmake PackageConfig files

This creates and installs a package version file and a package config
file. These are used by find_package with the CONFIG option, and are
roughly equivalent to pkgconfig, but is cmake specific rather than linux
specific.

v2: - Use configure_package_config_file() instead of config_file(),
      which generates helper macros and resolves relative paths allowing
      the entire install to be moved.
    - Update WaffleConfig.cmake.in to take advantage of
      configure_package_config_file()
    - Use SameMajorVersion instead of AnyNewerVersion for version
      compatibility. Since waffle uses apache's numbering scheme 2.0.0
      should not fulfill a requirement of 1.5.0 and vice versa.

Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>
cmake: Add the installed package files to the registry on windows

This adds the locations of the package files to the registry on windows,
which should allow them to be auto detected by cmake on windows when
linking against waffle in other projects.

Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>
cmake: remove FindWaffle.cmake

This is superseded by the WaffleConfig and WaffleConfigVersion cmake
files.