Docs: Add builtins documentation for cairo vm

[jimenezz22]

This PR is for the issue Builtins Documentation #326. Adding a complete documentation to understand how builtins works on cairo virtual machine and how bulitins perform complex operations at the cost of extra constraints when proving.

[rodrigo-pino]

To be honest, I liked the beginning but after that it all started feeling more and more as something generated by an IA and no honest effort put into it.

Some general feedback:

1. Is ok to write just what you understood of builtins.
2. If you wanted to write more, is ok for you to ask us questions, we will gladly answer or point towards some documentation.
3. Is ok to make mistakes

On the other hand is not Ok to fill the PR with content just for the sake of filling it with content. Usually the content doesn't adds anything meaningful, at instances, is slightly correct but it will cause more confusion than anything. Just by trying to run some Cairo Code (or reading the docs) you would realize that there are things written here that don't make sense (which begs the question, how much effort was put into this PR).

Some specific feedback:

1. The introduction can stay as is
2. What is builtins in Cairo and Builtins and Cairo memory should be explained as what they are without any analogies.
3. General types of builtins in Cairo VM: The concept is good, but it has builtins I don't know about. Also, sepcific builtins in Cairo Vm could be merged with this section.
4. Finally, How builtins perform ... should explain the trade-off that brings builtins to the table which has nothing to do with what was written in that section.

[jimenezz22]

Hi! @rodrigo-pino
I'm working on the changes and will make a new commit as soon as possible. Sorry for the use of analogies, I used them because it is easier for me to understand these types of concepts through the use of analogies and I thought it would be good to include them in the documentation. I will make documentation cleaner, shorter and with more technical language.

[jimenezz22]

@rodrigo-pino I already made the commit with the requested changes

[rodrigo-pino]

Much better @jimenezz22 ! Thank you. Just some comments

[jimenezz22]

Hi! @rodrigo-pino
I'll make a new commit as soon as possible

[rodrigo-pino]

@jimenezz22 do you have any updates on this?

[jimenezz22]

@rodrigo-pino I was waiting for you to answer the questions I had about the comments. In the next few hours you will have the issue ready

[jimenezz22]

@rodrigo-pino new commit ready

[rodrigo-pino]

Cool, just some nitpicks. Will approve once resolved

[jimenezz22]

@rodrigo-pino Changes made! Waiting for approval.

[TAdev0]

left minor comments. Looks good overall, a few improvments should be done but this can be done later in another PR