This reverts commit 3420a145, reversing
changes made to afb66a5a.

The current code base is not uniform. After some discussion,
we have chosen to go with double quotes by default.

[ci skip]

`bound_attributes` is now used universally across the board, removing
the need for the conversion layer. These changes are mostly mechanical,
with the exception of the log subscriber. Additional, we had to
implement `hash` on the attribute objects, so they could be used as a
key for query caching.