Considerations about a slimmer container base image than Ubuntu

Hello! Currently Ubuntu is used as base image for creating this container:

https://github.com/DNSCrypt/dnscrypt-server-docker/blob/8ea0501db173c81a8873a75db545ad9830c060a7/Dockerfile#L1

The Ubuntu base image is pretty *fat*, meaning a larger attack surface, a bigger size (80MB vs for example Alpine with <10MB) as well as possibly slightly worse performance on resource-constrained systems like Raspberry Pi's (_untested claim_).
Have you considered using a slimmer base image like Alpine, [Wolfi](https://github.com/wolfi-dev/) or [Distroless](https://github.com/GoogleContainerTools/distroless) (or even UBI)?

You [switched from using Alpine to Ubuntu in 2019](https://github.com/DNSCrypt/dnscrypt-server-docker/commit/cbf9f7c4ccd7d7aa9c7c5ae16929bf5be2c9450a) because "Rust doesn't work well with musl-libc" (quote from the linked commit message). These issues seem to be largely resolved by now, there is also an [official up-to-date Rust package in the Alpine package repository](https://pkgs.alpinelinux.org/package/edge/main/aarch64/rust).
The other mentioned base images like Wolfi do not use `musl` altogether.

Dockerfile の 1 行目と、Alpine から Ubuntu への切り替えを説明しているリンク先の 2019 年のコミットから始めます。置き換え候補のベースイメージとして Alpine、Wolfi、Distroless を比較し、その後イメージをビルドしてテストします。よりスリムなベースで resolver コンテナを壊さずに動作すれば完了です。

索引モデルが issue の本文から書いたものです。