Enable remote debugging with xdebug by default if enabled

[crittermike]

If xdebug is set to enabled in the environment.yaml, then xdebug.ini should probably have remote debugging turned on so it can be used right off the bat.

I did it on my end by adding the following lines to /config/php/fpm/conf.d/20-xdebug.ini and then running vagrant provision:

xdebug.remote_enable=On
xdebug.remote_autostart=On
xdebug.remote_connect_back=On