Solution for setting up binfmt_misc

After installing the qemu-user-binfmt package, the binary formats from /usr/lib/binfmt.d aren't registered automatically like they should.
The (a) solution is to put the following in /etc/wsl.conf:

```
[boot]
command = "shopt -s nullglob; for f in /usr/lib/binfmt.d/*.conf; do cat $f > /proc/sys/fs/binfmt_misc/register; done"
```
