[Refactoring] - Externalize methods from Translator.ex

[Dwctor]

Honey Potion gives to the user access to libraries to help writing eBPF programs, such as Honey.Ethhdr and Honey.Bpf_helpers. These libraries contain methods that translate directly to C code instead of going through the translation, allowing more power and customizability.

However, as it stands, the implementation of these libraries is located inside lib/honey/translator.ex in the to_c method. This can be hard to find, customize and improve. Ideally we should move the implementation of these libraries and their methods outside the Translator.ex and into the lib/honey/c_libraries so that contribution becomes easier and so that advanced users may customize the implementations of the C counterpart to their own use cases.

As an example the implementation of the Honey.Ethhdr can be found in lib/honey/translator.ex in the format:

def to_c({{:., _, [Honey.Ethhdr, function]}, _, params}, _context) do
  case function do
    :init -> ...
    :const_udp -> ...
    :ip_protocol -> ...
    ...
  end
end

and it should be moved to lib/honey/c_libraries into a module that defines the functions themselves, such as:

defmodule Honey.Ethhdr do

  def init() do
    ...
  end

  def const_udp() do
    ...
  end

  def ip_protocol() do
    ...
  end

  ...

end

Elixir has interesting ways to delegate function calls dynamically during execution, and a solution that leverages that to use the atom passed as a variable into the to_c function as the function name called in the library would be ideal, as it wouldn't require further changes into the translator.ex file for each new library.