Specify HTTP-network-or-cache fetch integration

[christhompson]

• Updates various objects to track IP address rather than IP address space (so they can be used more generally across both HTTP-network fetch and HTTP-network-or-cache fetch). Also updates various bits downstream (such as the "Integration with HTML") to reconcile with having IP addresses rather than IP address spaces on objects.
• Updates the "Local Network Access check" algorithm to operate on a request and an IP address (so that it can be called with either a connection in HTTP-network fetch or a response in HTTP-network-or-cache fetch).
• Adds an integration with HTTP-network-or-cache fetch to call into the "Local Network Access check" algorithm based on the saved IP address information in the stored response.
• Switches the "HTTP Cache" section under "Implementation considerations" to be explicitly non-normative notes on top of the specified integration with HTTP-network-or-cache fetch.
• Removes the "HTTP-no-service-worker fetch" definition as it is no longer relevant for LNA (without preflights).
• Adds a link to Add Permissions Policy integration with "allowed to use" check #59 to the TODO about checking permissions to better capture the current state of things.

This addresses part of Issue #104.

[annevk]

I thought I'd do some drive-by nits to make eventual upstreaming less of a hassle.

[christhompson]

I thought I'd do some drive-by nits to make eventual upstreaming less of a hassle.

Thank you for the review!