Replace query_file*!() variants with inherent support for include_str!() and other macros

[abonander]

Now that macro invocations in attributes are eagerly expanded, we can utilize this to replace query_file!("<path>") and variants with query!(include_str!("<path>")), which also gives us the ability to resolve paths relative to the current file (and eliminate about half the query*!() variants, a win for maintainability).

This would also allow use of concat!() and other string-manipulation macros in the input.