fix: list dependencies by invoking the interpreter on a binary

[lavafroth]

Fixes #3

Changes

• Creates a new module called ldd
• Parses the target binary's ELF headers
• Extracts the interpreter from the .interp section
• Calls the interpreter on the binary with the --list flag to query shared object dependencies
• Recursively parses the entire dependency tree

[creslinux]

This looks great - its definitely better then using the systems linker, thank you. If can remove the now defunct fn in exec we can merge

I'll update the docu/site this week to reflect the change to the helper.

[creslinux]

LGTM - thank you for the change