Add manticore-verifier tutorials

https://manticore.readthedocs.io/en/latest/verifier.html

https://blog.trailofbits.com/2020/07/12/new-manticore-verifier-for-smart-contracts/

We could revisit https://github.com/crytic/building-secure-contracts/tree/master/program-analysis/echidna, to have a common part that will work for both Echidna/manticore-verifier, and then advanced tutorials that would nightlight the specificities of each tool

Read the linked manticore-verifier documentation and blog post, then inspect the existing program-analysis/echidna material in building-secure-contracts. Define a shared tutorial section for Echidna and manticore-verifier, followed by advanced tool-specific tutorials; done means both tools are covered with their distinct capabilities explained.

Written by the indexing model from the issue text.