Adjust the loading of BAT from a wheel file in such a way that all
submodules are loaded in one go. This ensures that they're still
isolated from the rest of Blender (so other add-ons won't find our BAT),
but not from each other (so that there is only one copy of each
submodule).
In practice, this solves an issue where calling
`blender_asset_tracer.blendfile.set_strict_pointer_mode(False)` had no
effect. This was caused by each loaded submodule having a different copy
of `blendfile`.
Also loaded modules are logged more explicitly (at INFO level) to aid in
debugging later on.
2215ed2d85