First version of dind repo

[idodod]

1. Configure Earthfile targets to build, test & release images
2. Configure Renovate rules to get updates for docker version and alpine version
3. Configure Github Workflow to release new images to earthly/dind dockerhub repo after a successful merge of a Renovate PR that updates alpine and/or docker.

[idodod]

this will change to a commit hash.
Renovate is configured so that the commit hash will get updated every week (the intention is that this repo will use the most recent tests and dind installation script in earthly/earthly)