Write a README for factory-contract and cross-contract examples

[janedegtiareva]

The commands from readme fail.
To fix:

• Update the --initialBalance with the new formatting
• follow new account naming rules

[evgenykuzyakov]

This is for https://github.com/near/near-sdk-rs/tree/master/examples/cross-contract-high-level

[itegulov]

The README was very outdated and was purged in #761, repurposing this issue to rewrite the README for factory-contract and cross-contract examples

[HumbertoTM10]

I am applying to this issue via OnlyDust platform.

My background and how it can be leveraged

I have 4 years working in development environments, have encountered several challenges, requests and teams focusing in reusable and efficient code, so that gives me a better understanding of the code and how to solve problems efficiently.

How I plan on tackling this issue

I will deep dive into the commands in order to have clear understanding so I can traspass that into the Read Me so it becomes easy to understand.

[MattCS2006]

I am applying to this issue via OnlyDust platform.

My background and how it can be leveraged

I am very passionate for the new technologies, therefore lately I've been learning The Rust Language and I think that my knowledge on the language would be helpful to understand the code in order to explain it properly. Furthermore, I am a very dedicated person, so even if I encounter something that I don't understand, I research and take the time to learn so that I'm able to complete the task in the best way possible.

How I plan on tackling this issue

I would firstly take the time to deeply research about the new formatting and the new naming rules to make sure to do it exactly the way it is requested.
After researching and analyzing, I would get into the code to understand it and find the optimal way to explain it and show it in the README.

[frol]

This task requires Rust language experience, so I select @MattCS2006 for this challenge.

Here are the specific READMEs that needs to be completed:

• https://github.com/near/near-sdk-rs/tree/master/examples/factory-contract
• https://github.com/near/near-sdk-rs/tree/master/examples/cross-contract-calls

[frol]

@MattCS2006 Are you working on it? Please, create a PR today or I will give this issue to other contributors

[MattCS2006]

Hello @frol, hope you’re doing well!
Yes, I’m working on it, I’ll create the PR as soon as possible, thank you