First version of Cloudflare-dns-action

This action is a way to define a DNS record on Cloudflare through github actions.
It uses a bit of shell to import the record into terraform if it exists or create it if it doesn't,
then use a terraform plan is run to display the modifications to be done and a terraform apply will finish the operations in order to match the defined configuration in the action.
It can be used as a way for someone to automate the creation of a DNS record tied to a repository describing it's app easily !