Revert "Revert use of legacy buildpack"

This reverts commit 46862c46a27dc488832fc28c70e290aa472171ef.
Revert "Specify target directory"

This reverts commit c07a9211d9d1b328b72612f4bc308e96f9da75d9.
Modify stackato.yml for Stackato3 using CF-java-buildpack