Add additional configuration options

As a developer there are cases where I might need to increase some of the values we've hardcoded in Xdebug. For example: https://github.com/Chassis/Xdebug/blob/main/modules/xdebug/templates/xdebug.ini.erb#L8-L10 we should allow those to be configurable if they are set or fallback to the values we have set now.