Change build directory structure

[ivcosla]

Instead of building binaries in the project root do it in separated user-specified directory. The following structure is proposed by @evanlinjin

.build-dir/bin -> Binaries.
.build-dir/bin/apps -> App binaries.
.build-dir/configs -> Config files.
.build-dir/scripts -> Scripts for tests and other business

Also, ensure that every integration related script or resource is kept inside integration directory.