Convert code examples to live code

[qualidafial]

Wherever possible, convert the literal code examples in the developer guide to real code that gets run during Maven test phase.

This will protect against invalid code being published in the docs.

[stevenschlansker]

Would you consider making this post-release? We don't need to add new reasons to delay IMO. The docs are already of very high quality, in my opinion :smile:

(I changed the title anyway, but left it to you to decide to change the milestone)

[qualidafial]

Sure.

[hgschmie]

we never made that a rule / priority. While there are some examples that are doc code, others are not. It is not hard, just a lot of work. Might be a good way to get into Jdbi development.