move builder build_package performance transaction parent, add spans

[syphar]

So, I really hope that this fixes the issue.

Generally:

• I moved the transaction parent up one level, so everything we do for one build is in that transaction. Missing previously: toolchain updates, builder docker image download / update
• I used the new block_on with tracing in the build queue
• After having slept I now feel like Deref is wrong for this use-case, there are cases where people would accidentally call the wrong method.
• I fixed the default log-directive (though this directive is overwritten anyways on the server).

This time I locally ran the old build-server (via daemon), and new (via builder-binary), and in both cases I only saw the parent-transaction I want, and never the parent-less child spans we see in prod.

[syphar]

@GuillaumeGomez this can be reviewed now