Do some better erroring if you can't launch the mysql binary

[uberbrady]

When an error happens during php artisan snipeit:restore, we give a rather generic error message.

This tries to:

1. Set the standard-out and standard-error to non-blocking - so we can read as much or as little from those streams as is available, without blocking the rest of the process.
2. We now wrap most of the process of reading from the .sql dump file around a try/catch . And if we have a failure to write to the pipe to mysql - either with a return of false from fwrite(), or via an exception - then we dump stdout and stderr to the logs, and to the console.

This should hopefully make it easier for us to troubleshoot when restores fail due to systems level issues. (Problems we've run into, in the wild - being unable to execute the mysql binary, and missing libraries that are necessary to run mysql).