Revert "Stop forcing binaryDir"

It's integral to the CI setup, even though it causes collisions with
VSCode builds. See
cpp-best-practices/cmake_template#91

This reverts commit 2e880a4.

CMakePresets.json

@@ -11,6 +11,7 @@
             "description": "General settings that apply to all configurations",
             "hidden": true,
             "generator": "Ninja",
+            "binaryDir": "${sourceDir}/out/build/${presetName}",
             "installDir": "${sourceDir}/out/install/${presetName}"
         },
         {