DFS TZIP

[cct]

Request for comments on the DFS proposal. The comments can be left below.

[rafoo]

There have been some comments on the tzip draft MR (https://gitlab.com/tzip/tzip/-/merge_requests/111) but this is also a recurring topic here; here is a list of related discussions:

• Problems with Concurrency
• Concurrency, BFS vs DFS (and a proposal)
• Smart contract vulnerabilities due to Tezos’ message passing architecture