MySQL: Support for LOAD DATA INFILE

[andygrunwald]

What would you like to be added:

Row-Inserts are done via (bulk) inserts right now.
For bigger imports, MySQL provides a LOAD DATA command.
See 13.2.7 LOAD DATA Statement @ MySQL docs.

Adding support for this command would be cool.

Why is this needed:

This would speed up the import process of bigger CSV datasets quite significantly.

Anything else we need to know?:

Dedicated speed tests haven't been done yet.

This is similar to the PostgreSQL COPY variant mentioned in #44 and #47.