Change docker image from Alpine to Debian

[wfondrie]

I was having trouble with interoperability using a Alpine-based image (mostly trying to use the AWS CLI, even through the host system). I think transitioning to a Debian-based image that uses glibc instead of musl would resolve some headaches 🙃.

[lazear]

I haven't benchmarked musl vs glibc for Sage specifically, but I know people have reported big differences in performance for other Rust applications due to different system allocators used (with musl binaries generally performing worse)

[lazear]

I just tried out the v0.6 binaries on PXD005590. Musl builds are > 3x slower than the gnu builds :/

I think that suggests that exploring some non-standard perf focused allocators (mimalloc?) could yield fruit too.