Simplification of Process API/interface and implementation of Process.Executable

[renatomassaro]

Process.Executable is an interface for easily defining how a process should be executed. It is a much cleaner and simpler interface compared to the one we were using previously. Plus, it's a lot less prone-to-error and a lot more extensible.

• [x] Interface
• [x] Docs
• [x] Tests
• [x] Adapt existing processes to the new Executable format.
  • Mostly. The ones missing should be updated/adapted as the need arises.
• [x] Typespecs

TODO

• New henforcers:
  • [x] Test
  • [x] Doc
  • [x] Type

Incidental

• Enhancements on henforcers used by ServerJoin
  • Refactored ChannelHenforcer (Server)
  • Overall Henforcers improvements
• Simplified FileFlow to execute the corresponding Process.Executable directly
  • Removed FileFlow backends (CrackerFlow, FirewallFlow, LogForgerFlow, etc)
• Renamed ProcessType to Processable
• Simplified Processable interface

This change is 

[sourcelevel-bot[bot]]

Ebert has finished reviewing this Pull Request and has found:

• 12 possible new issues (including those that may have been commented here).
• 7 fixed issues! 🎉

You can see more details about this review at https://ebertapp.io/github/HackerExperience/Helix/pulls/316.

[renatomassaro]

Reviewed 88 of 88 files at r1. Review status: all files reviewed at latest revision, 4 unresolved discussions.

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lib/process/objective.ex, line 156 at r1 (raw file):

            ulk: calculate(:ulk, params, factors)
          }
          |> Enum.reject(fn {_, total} -> total == nil end)  # Test me

?

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lib/software/websocket/requests/pftp/file/download.ex, line 89 at r1 (raw file):

    storage = request.meta.storage

    #

?

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lib/universe/bank/process/bank/transfer.ex, line 52 at r1 (raw file):

    # Review: Not exactly what I want. Where do I put limitations?
    # TODO: Once TOP supports it, `minimum` should refer to raw time, not

Create issue: process resources should be defined at the same abstraction of process_objective.

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test/features/hack_test.exs, line 50 at r1 (raw file):

      # Wait for response
      assert_reply ref, :ok, response, 300  # TODO

Remove - or create a macro based on env (slow_test -> 500; test -> 100)

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