Motivation for this change

Upgrades moto and adds a patch which removes moto's dependency on boto. From getmoto/moto#3503:

The boto library (long ago superseded by boto3) has not had an official
release in over two years or even a commit in the last 18 months. Importing
the package (or indirectly importing it by via moto) generates a deprecation
warning. Additionally, an ever-increasing number of moto users who have
left boto behind for boto3 are still being forced to install boto.

Also, boto is broken for python3.9, and moto is a dependency of pandas, so this meant that pandas was broken on python3. Since so many things depend on pandas, I have not built the entire set of dependencies. I assume it will be large.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.