WIP: Make melpazoid as Elisp package and build tool like Cask

[conao3]

Re #4, discussed in #3.

• The Elisp package allows us to run locally without being tied to running on a CI.
• With async-await, all processing is done asynchronously.
• We can write meta information to melpazoid by placing a Melpazoid file similar to the Cask file.
• Melpazoid describes dependencies as package meta information and supports multiple packages.
• Melpazoid allows you to write recipes that are fully compatible with MELPA and parse and interpret Elisp files in exactly the same way.
• No longer Python dependency. Depends only Emacs.
• Packages are distributed by package.el through MELPA, not by pip. This is the most familiar method for Elisp developers.

[riscy]

Hi @conao3 - I think melpazoid went in a different direction in this PR; but given your significant changes, maybe you wanted to create a fork of melpazoid? I would totally welcome this if it's easier for folks to work with.

[conao3]

Long time no see, @riscy! Honestly, I cannot take time on this area recently. Sorry, I had also forgotten that I created this draft PR. I will close it once.

[akirak]

keg.el, which was published a couple of months after the last commit in this PR, seems to be what @conao3 had intended to achieve. He ended up rewriting melpazoid in Emacs Lisp rather than fork, so this PR should be no longer relevant.