Path 2: update rcgen to version 0.13.1

[haurog]

As described in #5590 this PR shows all the necessary changes for update path 2.
In this solution, rcgen and webrtc is updated to the newest version which makes substantial code changes necessary.

Notes & open questions

I do not know the code base well enough to make sure I did not break anything here. All the tests (minus doc test) work and I also built lighthouse which depends on libp2p2-tls and it works flawlessly, so I do not think I broke anything obvious.

I did not change the documentation which is why doctest tests fail.

Change checklist

I did not do the changes described below. I can do this once it is decided which update Path is the one to go.

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

[jxs]

Hi, and thanks for this! I definitely prefer this path as Path1 as I had started the same procedure on #5448 but haven't yet had time to fix the tests, do you wanna take it over? that would be great!
Thanks!

[haurog]

That is awesome. I will definitely have a look at it and see if I can fix the test.

[mergify]

This pull request has merge conflicts. Could you please resolve them @haurog? 🙏

[jxs]

going to close this one then