[yabridgectl] Clean up VST3 bundles

We would completely remove VST3 bundles that yabridgectl does not know
about anymore, but we would not remove leftover files within bundles.
This could otherwise cause issues when messing with 32-bit and 64-bit
versions of plugins or yabridge itself.

CHANGELOG.md

@@ -70,6 +70,11 @@ Versioning](https://semver.org/spec/v2.0.0.html).
 
 - Added support for setting up merged VST3 bundles with a 32-bit version of
   `libyabridge-vst3.so`.
+- Merged VST3 bundles set up in `~/.vst3/yabridge` are now always cleared before
+  yabridgectl adds new files to them. This makes it easier to switch from the
+  64-bit version of a plugin to the 32-bit version, or from a 64-bit version of
+  yabridge to the 32-bit version. I don't know why you would want to do either
+  of those things, but now you can!
 - Copies of `libyabridge-vst2.so` and `libyabridge-vst3.so` are now reflinked
   when supported by the file system. This speeds up the file coyping process
   while also reducing the amount of disk space used for yabridge when using