Successor of #10280 after it was reverted in #10592.
Re-introduce the usage of diesel-async again, but now also add TLS
support so that we connect to the storcon database using TLS. By
default, diesel-async doesn't support TLS, so add some code to make us
explicitly request TLS.
cc https://github.com/neondatabase/cloud/issues/23583
We now don't need libpq any more for the build of the storage
controller, as we use `diesel-async` since #10280. Therefore, we remove
the env var that gave cargo/rustc the location for libpq.
Follow-up of #10280
Closes: https://github.com/neondatabase/cloud/issues/17784
## Problem
Currently, we run the whole CI pipeline for any changes. It's slow and
expensive.
## Suggestion
Starting with MacOs builds:
- check what files were changed
- rebuild only needed parts
- reuse results from previous builds when available
- run builds in parallel when possible
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Co-authored-by: Alexander Bayandin <alexander@neon.tech>
