dynamic linkage checks

It would be great to be able to check linkage.
It's currently possible with `commandTests`, but only if `ldd` is present (often not the case for minimal images) and it requires matching the output, which can be tricky to actually implement.

Example:

```YAML
elfBinaryTests:
- name: "bash is dynamically linked"
path: "/bin/bash"
noMissingLibs: true
libraries:
- "linux-vdso.so.1"
- "libtinfo.so.6"
- "libdl.so.*"
- "libc.so.6"
- "ld-linux-*.so.*"
```