docs: payment verifications & internet identifiers

[ATXMJ]

@mistakia do you think the Internet Identifiers content should be extracted to a different page?

[mistakia]

@mistakia do you think the Internet Identifiers content should be extracted to a different page?

Think it's fine to keep as a single page for now.

We haven't really established a guideline for when a page should be broken into sub-pages. It should occur when a certain number of distinct sections exist and the page exceeds a certain length. I think we've yet to clearly exceed those thresholds here.

[ATXMJ]

I've removed the section on amount-based payment verification.

@mistakia anything else you'd like changed before we merge this?

I'm seeing more identifier services coming online, and would like to encourage them to adopt these protocols.

[Zosoled]

I propose the following for the <local-part> of the .well-known/nano-currency.json implementation:

• The server MAY accept combination of uppercase and lowercase letters.
• The server MUST save the primary key of the entry as all lowercase.
• The server MAY additionally save the original casing of the entry for front-end display.
• The server MUST prevent case-insensitive duplicates of the <local-part> (e.g. existing entry 'JohnDoe' prevents a new entry 'johndoe', 'JOHNDOE', etc.)
• The server MUST convert the <local-part> of incoming queries to lowercase in order to look up the proper primary key.

EDIT: Obviously if there is a better way to word all that, feel free to change it up.