Added Zero Copy article

[akshatcoder-hash]

New Addition: Added a tutorial to implement zero copy in anchor.

[akshatcoder-hash]

could you please give a review? @acheroncrypto

[acheroncrypto]

Hey, sorry for the late review!

Thank you for taking the time to write this but unfortunately zero copy is an advanced concept and this PR doesn't meet the standards of other parts of the book:

• There is no explanation of memory layouts, alignments which is at the core of zero copy
• There is no mention of possible pitfalls
• The reasoning for the difference between normal and zero-copy version of the program is incorrect
• Roughly half of the text is unnecessary analogies as if the advanced concept section is written for 5 year olds, for example:

  • Now for the cool part. We're going to tweak our program to use zero-copy. Imagine we're adding some fancy features to our locker...

  • We're checking the transaction fees and account changes - kind of like getting a receipt after you buy something....

  • When we used zero-copy, it cost a bit more in transaction fees. It's like paying extra for express delivery because you're getting a more complex service...

This would have to be completely rewritten in order to be suitable for the advanced section of the book.