Add prepared queries to ODBC.jl

[galenlynch]

This pull request adds the ability to use prepared statements in result returning queries. This required the following changes:

1. Adding a stmt field to ODBC.Source to allow the use of either a DSN statement pointer or a prepared statement pointer in ODBC.jl functions

2. Adding a constructor methods to ODBC.Source and ODBC.query that accept prepared statements.

3. Moving code to bind values to parameters from execute! into its own function, bind_vals!

4. Moving the code to build a ODBC.Source object from a statement pointer into its own function, build_source

I have additionally added a number of type decorations to methods in Source.jl, as well as splitting some very long lines of code into multi-line statements.

I have updated the documentation to reflect these changes.

[galenlynch]

The build fails because of this bug in Julia: #22256.

[galenlynch]

Bump, I think the tests should pass now that the issue in Julia was resolved.