Actually when we use the command `ynh_use_logrotate /var/log/abcd/` the result in the logrotate conf file is `/opt/yunohost/abcd/logs//.log` witch is not what we want.
* New helpers ynh_add_systemd_config and ynh_remove_systemd_config
Standard file for systemd service.
* ynh_subsistute_char was renamed ynh_replace_string
* Upgrade helpers
* Add some description of which keywords are replaced by which variable
* New helpers ynh_add_nginx_config and ynh_remove_nginx_config
Standard configuration of nginx
Use local files stored in conf/, so it's still possible to use a specific config
* ynh_substitute_char was renamed ynh_replace_string
* ynh_compare_checksum_config -> ynh_backup_if_checksum_is_different
* Upgrade helpers
* Add some description of which keywords are replaced by which variable
* New helpers ynh_add_fpm_config and ynh_remove_fpm_config
Standard configuration of php-fpm.
Use local files stored in conf/, so it's still possible to use a specific config
* ynh_substitute_char was renamed to ynh_replace_string
* Update checksum command and quiet the second secure_remove
* Fix helpers name
