Review/rewrite how-to for account contracts

[critesjosh]

Review / rewrite this page based on feedback

https://docs.aztec.network/developers/contracts/writing_contracts/accounts/write_accounts_contract

• says we should understand how accounts are defined and links here for that: https://docs.aztec.network/learn/concepts/accounts/main
• but that doc is confusing. some super basic concepts are missing like:
• how do I go from 0 to 1? like how do I deploy a smart account contract if I don't have an account already?
• descriptions of the actually pre-existing account contract types and what properties they have (i see links to tests for things, and did manage to find a list in the aztec.js documentation, but no links to the actual contract code anywhere)
• the fee management stuff is confusion. I guess there are no fees right now so I don't need to worry about paying for anything? or if there are fees, do I need to pay some third party who is already bootstrapped to create my account?|