Add support to inspect ELF binaries

[cgzones]

New columns:

• hardening options

  • stack-protector
  • fortified functions
  • relro, now
  • rpath
  • runpath
  • pie
  • nx

• elf type (32/64-bit)

• runpath

TODO

• elf type for arm
• Clang CFI

[BenBE]

@cgzones What's the status of this?

[alarixnia]

Would be nice if the ELF inspection bits were moved out of the Linux directory if you're still interested in working on this, libelf is available on most htop platforms, not just Linux, and I'd find the feature to inspect hardening flags very useful on NetBSD

[BenBE]

@cgzones What's missing to finalize this one?