Update guide: Install and deploy a smart contract with code

[briwylde08]

https://developers.stellar.org/docs/build/guides/transactions/install-deploy-contract-with-code

[Alouzious]

@briwylde08 I'd like to take this issue. I'll go through the current guide, identify what's outdated and open a PR with the fixes.

[briwylde08]

@Alouzious sorry for the delayed reply as I was out of office. You are more than welcome to take it!