Add module config

Modules might need to have custom options. This creates the file on `mods-available` and symlinks them to `conf.d`, both at `/etc/php5`.

## To dos
- support 5.3
```
{% if item.extension_name is defined %}
    extension = {{ item.extension_name }}.so
{% else %}
    extension = {{ item.name }}.so
{% endif %}
```

This would allow loading a different extension than the one in the filename, allowing (for example) loading `apcu.so` inside `apc.ini` file.