removal(terraform): Remove Hedgedoc Demo instance

terraform/hedgedoc-demo/.terraform.lock.hcl

terraform/hedgedoc-demo/README.md

terraform/hedgedoc-demo/dns.tf

terraform/hedgedoc-demo/firewall.tf

terraform/hedgedoc-demo/main.tf

terraform/hedgedoc-demo/provider.tf

terraform/hedgedoc-demo/schema.excalidraw

terraform/hedgedoc-demo/schema.svg

terraform/hedgedoc-demo/ssh.tf

terraform/hedgedoc-demo/templates/cloud-init.tpl

terraform/hedgedoc-demo/templates/docker-compose.tpl

terraform/hedgedoc-demo/terraform.enc.tfvars

terraform/hedgedoc-demo/variables.tf

terraform/hedgedoc-demo/versions.tf