testbench: dont build testbench, tools and topologies in the source directory

[lgirdwood]

Currently all topologies, testbench and some tools are built within the FW source directory unlike FW which has separate binary destination directories outside of the main FW source directory.

This series moves all tools, testbench and topologies binaries to outside the source directory to the parent SOF "workspace" directory alongside the FW build output directories.