docker(install): allow specifying custom lima images

[crazy-max]

related to https://github.com/crazy-max/ghaction-setup-docker/actions/runs/7158220214/job/19490045126?pr=48#step:3:146

/usr/local/bin/limactl start --name=docker-actions-toolkit --tty=false
  time="2023-12-10T13:49:57Z" level=info msg="Using the existing instance \"docker-actions-toolkit\""
  time="2023-12-10T13:49:57Z" level=info msg="QEMU binary \"/usr/local/bin/qemu-system-x86_64\" seems properly signed with the \"com.apple.security.hypervisor\" entitlement"
  time="2023-12-10T13:49:57Z" level=info msg="Attempting to download the image" arch=x86_64 digest="sha256:054db2d88c454bb0ad8dfd8883955e3946b57d2b0bf0d023f3ade3c93cdd14e5" location="https://cloud-images.ubuntu.com/releases/22.04/release-20231026/ubuntu-22.04-server-cloudimg-amd64.img"
  Downloading the image (ubuntu-22.04-server-cloudimg-amd64.img)
  time="2023-12-10T13:50:02Z" level=fatal msg="failed to download \"[https://cloud-images.ubuntu.com/releases/22.04/release-20231026/ubuntu-22.04-server-cloudimg-amd64.img\](https://cloud-images.ubuntu.com/releases/22.04/release-20231026/ubuntu-22.04-server-cloudimg-amd64.img/)": read tcp 192.168.64.23:49180->185.125.190.37:443: read: connection reset by peer"
Error: The process '/usr/local/bin/limactl' failed with exit code 1

Ubuntu or debian mirrors to download cloud images can be flaky on macOS runners so to avoid blocking users, they can provide their own image if they want to.