added variables and default values

defaults/main.yml

 ---
-php_module_config_file: "module.ini.j2"
-php_module_priority: <module prio> 
+php_module_config_file: "apcu.ini.j2"
+php_module_priority: 20
+php_mod_apcu_enabled: true
+php_mod_apcu_shm_segments: 1
+php_mod_apcu_shm_size: "32M"
+php_mod_apcu_entries_hint: 4096
+php_mod_apcu_ttl: 0
+php_mod_apcu_gc_ttl: 3600
+php_mod_apcu_mmap_file_mask: ""
+php_mod_apcu_slam_defense: 1
+php_mod_apcu_enable_cli: false
+php_mod_apcu_use_request_time: false
+php_mod_apcu_serializer: "php"
+php_mod_apcu_coredump_unmap: false
+php_mod_apcu_preload_path: "" 

vars/Debian-10.yml

 ---
-package_packages: ["php7.3-<module>"]
+package_packages: ["php-apcu"]

vars/main.yml

 ---
-php_module_name: "<module name>"
+php_module_name: "apcu"