feat(mysql): support load data local infile

[joelwurtz]

Hello,

This PR intend to add support for query like LOAD DATA LOCAL INFILE ...

It fixes #1766
I have taken some inspiration from this PR : #2738 (which has been closed)

I also look at the comment to see blockers of the previous PR, i think this one should be in the right direction :

• It does not use a new buffer (it uses the same "hacky" implementation as pgsql by reserving four bytes before copy to existing buffer and rewrite it before flush)
• It support directly the query LOAD DATA LOCAL INFILE there is no new api for end user
• However it is generic enough in the implementation to be able to send any stream (which means we could create a new method above it to send any stream to mysql not just a file, not done in this PR as i think this is out of scope, let's just support the basic query for now
• I added a new method to get an AsyncRead from any file so it can support all runtimes

The only thing that i'm not sure off, is the "hack" when copying the stream, since normal packet have a check for size excedding 16mb (0xFF_FF_FF) this is not done here to not complexify, but since the buffer capacity is 8192 i don't see case where this may happens ?

Let me know if this need to be checked also.