Repository: elftoolchain

Motivation

As per discussion in falcosecurity/libs#2175 I would like to transfer our local fork (with minimal modifications) of the elftoolchain project (https://sourceforge.net/p/elftoolchain/wiki/Home/) currently living in my account https://github.com/LucaGuerra/elftoolchain to the falcosecurity organization as it is now a (possible) dependency in falcosecurity/libs. I propose the repo OWNERS to be exactly the same as libs.