Rename Airflow files to apache-airflow

Rename Airflow-related files to include the 'apache-' prefix for consistency with the upstream project. Renamed: ct/airflow.sh -> ct/apache-airflow.sh, install/airflow-install.sh -> install/apache-airflow-install.sh, json/airflow.json -> json/apache-airflow.json. Also update APP variable in ct script from "Airflow" to "Apache-Airflow".

ct/apache-airflow.sh

@@ -5,7 +5,7 @@ source <(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxV
 # License: MIT | https://github.com/community-scripts/ProxmoxVED/raw/main/LICENSE
 # Source: https://github.com/apache/airflow
 
-APP="Airflow"
+APP="Apache-Airflow"
 var_tags="${var_tags:-workflow;scheduler;automation}"
 var_cpu="${var_cpu:-2}"
 var_ram="${var_ram:-4096}"