Add alpine build

[jprendes]

This PR adds support for building alpine binaries.

The main changes:

• Add a build argument to the Dockerfile to specify the base image.
• Update the bake file to account for the new argument
• Move some of the logic from the Dockerfile to a shell script that handles the different base images.
• The name of the tar archives now end with -gnuor -musl (for debian and alpine respectively).
• Bumped wasmedge-sdk to 0.11.2 (required for building with alpine Add options to allow generating statically linked binaries WasmEdge/wasmedge-rust-sdk#48).
• Add a feature to vendor the dbus crate (so that it links statically)

Result:

$ docker buildx bake bins-cross tar-cross
# ... 4 parallel builds, go get a coffee ...

$ ls bin
alpine-amd64  alpine-arm64  bullseye-amd64  bullseye-arm64

$ ls bin/alpine-amd64/
containerd-shim-wasmedged-v1  containerd-shim-wasmtimed-v1  containerd-wasmedged
containerd-shim-wasmedge-v1   containerd-shim-wasmtime-v1   containerd-wasmtimed
# same output for bin/alpine-arm64, bin/bullseye-amd64, and bin/bullseye-arm64

$ ls release/
containerd-shim-wasmedge-linux-amd64-gnu.tar.gz   containerd-shim-wasmtime-linux-amd64-gnu.tar.gz
containerd-shim-wasmedge-linux-amd64-musl.tar.gz  containerd-shim-wasmtime-linux-amd64-musl.tar.gz
containerd-shim-wasmedge-linux-arm64-gnu.tar.gz   containerd-shim-wasmtime-linux-arm64-gnu.tar.gz
containerd-shim-wasmedge-linux-arm64-musl.tar.gz  containerd-shim-wasmtime-linux-arm64-musl.tar.gz

$ ldd bin/alpine-amd64/containerd-shim-wasmedge-v1 
        statically linked

$ ldd bin/bullseye-amd64/containerd-shim-wasmedge-v1 
        linux-vdso.so.1 (0x00007ffe1e1b8000)
        librt.so.1 => /usr/lib/librt.so.1 (0x00007f33f077d000)
        libdl.so.2 => /usr/lib/libdl.so.2 (0x00007f33f0778000)
        # ... and more ...

[jsturtevant]

LGTM, though I not really familiar with these tools. left a few non-blocking comments

[Mossaka]

LGTM!

[Mossaka]

Thanks for contributing!! I am going to merge and can do a release tomorrow.