docs: fix dead links to kenreitz.org

[tswast]

I noticed a few dead links. Looking back through the wayback machine, I was able to find the new location of these articles.

[tswast]

@duzhuoshanwai perhaps you could take a look since you most recently touched this documentation? Thanks!

[tswast]

Or maybe @nateprewitt who reviewed #6899

[nateprewitt]

At this point I'd prefer we just remove these links. We get PRs every few years whenever the domain changes.

[duzhuoshanwai]

Shouldn't we asking kennethreitz himself, since this is his website?

[tswast]

I think there's some useful information in both of those remaining links. Maybe I try to paraphrase or summarize to include them directly on the docs site?

[sigmavirus24]

Be cordial or be on your way, isn't a code of conduct and being under the PSF we adhere to that. We should instead link to that CoC

[sigmavirus24]

Also the post about the future from 13 years ago, isn't relevant any longer. We just haven't edited and pruned our docs in a long while to remove references to it

[tswast]

Thanks for the feedback! Indeed, as I look deeper into the Transport Adapters justification, it doesn't appear that the original vision of unifying WGSI, Flask, Requests, etc. with common base classes wasn't actually achieved, so that document may be doing more harm than good at this point.

Removed both of the remaining links in 6716d7c