Add Security Best Practices Section to Linea Docs

[drnick30]

Description

The documentation currently lacks a dedicated section on security best practices for developers building on Linea. This proposal suggests adding a new section to cover common security concerns and how to mitigate them.

Suggested Content:

• Proper use of smart contract permissions.
• Avoiding common vulnerabilities like reentrancy and integer overflow.
• Secure storage of private keys and environment variables.
• Best practices for interacting with external contracts.
• Tips for testing and auditing smart contracts.

Where should this content be added?

Proposed Location in Docs:
The security section should be placed under docs/get-started/security.md or a similar location.

[jlwllmr]

@drnick30 good suggestion! will see if I can get round to this at some point. If not, happy for you or others to have a go.