We standarized on using `rustls` as a TLS implementation across the
monorepo, which is written in Rust and has better ergonomics,
integration with the Rust ecosystem, and consistent behavior among
platforms. However, the Labrinth Clickhouse client was the last
remaining exception to this, using the native, OS-provided TLS
implementation, which on Linux is OpenSSL and requires developers and
Docker images to install OpenSSL development packages to build Labrinth,
in addition to introducing an additional runtime dependency to Labrinth.
Let's make the process of building Labrinth slightly simpler by
switching such client to `rustls` as well, which results in finally
using the same TLS implementation for everything, a simplified build and
distribution process, less transitive dependencies, and potentially
smaller binaries (since `rustls` was already being pulled in for, e.g.,
the SMTP client).
* dist(docker): add `.dockerignore` as symlink to `.gitignore`
This ensures that no files outside of version control are transferred to
the Docker build context for Labrinth and Daedalus images, which
significantly improves build speed (if a `target` directory is already
present) and build reproducibility.
* chore(dist/docker): simplify out unneeeded statements, move `SQLX_OFFLINE` env var setting to build command itself
The latter approach ensures that developers building the image locally
don't forget to set `SQLX_OFFLINE`, too.
* dist(docker): add `curl` package to Labrinth image
