[wix-devs] migrated Sql extension

[Sean Hall]

I was mostly successful in migrating the Sql extension to its shiny new
micro repo, but I ran into some problems.

1. There must be a script or something to migrate the messages.xml to the
new C# class. I did it manually since there were only 4, but don't really
want to do that again.

2. There must be a script or something to generate the tuple definitions. I
didn't even want to try to do that manually. The test that I checked in is
failing, and I'm guessing that's because tuple definitions are required?
When is the tables.xml used now?

3. I don't know how to setup the Appveyor stuff, I'm guessing I don't even
have access to it.