Dockerfile.fpm-alpine

* Add docker secret support

* Add docker secret support to selected environment variables below:

- APP_KEY_FILE        -> APP_KEY;

- DB_HOST_FILE        -> DB_HOST;
- DB_PORT_FILE        -> DB_PORT;
- DB_DATABASE_FILE    -> DB_DATABASE;
- DB_USERNAME_FILE    -> DB_USERNAME;
- DB_PASSWORD_FILE    -> DB_PASSWORD;

- REDIS_HOST_FILE     -> REDIS_HOST;
- REDIS_PASSWORD_FILE -> REDIS_PASSWORD;
- REDIS_PORT_FILE     -> REDIS_PORT;

- MAIL_HOST_FILE      -> MAIL_HOST;
- MAIL_PORT_FILE      -> MAIL_PORT;
- MAIL_USERNAME_FILE  -> MAIL_USERNAME;
- MAIL_PASSWORD_FILE  -> MAIL_PASSWORD;

* Add env file for docker secrets

* Added #9313: add new fpm-image using docker secrets

* Fix broken symlinks

* Add docker secrets support using shell script

* Remove old docker config php files