docs: ETH Account Funding Guide

[sgerodes]

I have encountered several problem when doing the first setup. I have found the documentation not good enough to get started. Fixed the documentation. This FIx will help newcommers to seamlesly start start working with this project.

[bh2smith]

Thanks @sgerodes for your suggestions. I've made a few inline comments and suggestions that could improve your contribution.

To summarize, I would propose:

1. Remove the .env file creation description since it is already above in the Local Testing section.
2. Remove the opensea example from the Local Testing section, since the user hasn't yet been instructed to fund their ETH account. We can then use your send-eth in the place you've included it a simpler script.
3. Elaborate on the "Fund your account guide" by adding a getEthAddress script to the examples and instructing the user to run that in order to determine the ETH address associated with their near account.

Furthermore, this might be a good place to include a try-catch block directly in the project with a more human readable error that the account they are trying to build a transaction for is not funded:

This part here is the core of the error (when trying to get gas estimates for the transaction payload)

https://github.com/Mintbase/near-ca/blob/a1d3c557e19b68e13587a0d520b82813179fa1e3/src/utils/transaction.ts#L44-L49

However, it might not hurt to put a more generic try-catch around the call to populateTx here

https://github.com/Mintbase/near-ca/blob/a1d3c557e19b68e13587a0d520b82813179fa1e3/src/chains/ethereum.ts#L160-L164

[sgerodes]

@bh2smith I have changed the docs according to your review

[bh2smith]

Hey this looks much better thanks. There is another PR that will conflict with a few of these changes, but otherwise it looks good. I guess you're not going to introduce the try-catch?