Update erc-1.md

[Aboudjem]

I've proposed key updates to the ERC-1 draft, aligning it closely with the needs of the Ethereum community post the EIP/ERC split. Key changes include:

• Clearly categorizes ERCs as either 'Standalone' or 'Dependent', specifying existing ERCs they relate to.
• Code Quality and Documentation Standards
• Content Guidelines
• Subcategory Management in a Dedicated ERC: Proposes a separate ERC for managing subcategories, allowing dynamic updates and consistent use across ERCs.
• Ensures auxiliary files are size-optimized for efficient repository management.

These enhancements aim to make ERC-1 a robust, clear, and adaptable guideline for the community.