Upgrade pingcap parser (for MySQL)

[akutschera]

What do you want to change?

The pingcap parser used to parse MySQL statements has moved to a new github repository (see README

Upgrading it would require a new import statement for the dolphin engine.
It would also solve #1197 and #1754 (at least the parse errors will be gone).

What database engines need to be changed?

MySQL

What programming language backends need to be changed?

Go