[Enhancement]: Improve "Obtaining NEX account details" section of README

[jonbarrow]

Checked Existing

• I have checked the repository for duplicate issues.

What enhancement would you like to see?

Improve the "Obtaining NEX account details" section of the README to have more up to date information. Currently the steps for the Wii U only list using a proxy server and manually searching the account.dat. This is not necessary, homebrew like HokakuCafe can dump this data (the file written by this hook contains the NEX username and password)

The 3DS steps also instruct users to download a homebrew app from 9net. While we know this was written by Stary, other people may not be so trusting. We should probably provide the source for these apps here in this repo?

Any other details to share? (OPTIONAL)

No response