Proper TCP socket shutdown; Generic TCP timeout utils; built-in HTTP server timeouts; update docu

[ivmarkov]

This PR implements:

• A TcpShutdown trait with proper socket close and abort functionality for both STD and embassy-net. Needs testing for embassy-net
• Generic TCP "timeout" decorators in edge_net which can be used by anyone
• Built-in timeouts (both for each IO operation, as well as for the whole request-response) for the HTTP server

[AnthonyGrondin]

I tested with esp-wifi + embassy-net and I can confirm that this fixes the issues I've been having with closing connections:

Here's a trace for a request issued with "Connection: Close" and following the redirection.

Here's a trace for a request issued with "Connection: Keep-Alive" and following the redirection.

[AnthonyGrondin]

LGTM.
Thank you very much for taking care of this.

If some additional optional parameters are ever added to run(), it may become more user friendly to switch to a builder pattern, but at this point, this is more about UX than usability, and we should focus on usability for now.

[ivmarkov]

If some additional optional parameters are ever added to run(), it may become more user friendly to switch to a builder pattern, but at this point, this is more about UX than usability, and we should focus on usability for now.

Agreed. A builder pattern can wait a bit.