Add DNS plugin for All-Inkl provider

[mobilandi]

So far there was no certbot Plugin for the big German provider All-Inkl.
I built that plugin and tested it for Cert Requests via DNS-Challenge. Everything worked fine for new.
I thought it would be nice to add this to the main project. It's my first python project and also my first git PR. So feel free to criticize if something else needs to be done. Thank you.

[nginxproxymanagerci]

CI Error:

/bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
certbot-node: Pulling from nginxproxymanager/nginx-full
55a95237d05e: Pulling fs layer
b3aa25c040eb: Pulling fs layer
0347dcb76707: Pulling fs layer
ff811290060a: Pulling fs layer
60dd07915845: Pulling fs layer
5e789b64fc31: Pulling fs layer
04795e9ec375: Pulling fs layer
b2964fb1c339: Pulling fs layer
f6401c83faed: Pulling fs layer
8e2567281c84: Pulling fs layer
7cf6db5741a2: Pulling fs layer
e91105a42626: Pulling fs layer
c6be318cb8bb: Pulling fs layer
88e35f00eecc: Pulling fs layer
5654b802c6ab: Pulling fs layer
6d7fe3139aab: Pulling fs layer
358282204810: Pulling fs layer
363db42276e0: Pulling fs layer
87a58e95f8aa: Pulling fs layer
28c358a22b3f: Pulling fs layer
f16d44d35d39: Pulling fs layer
c9ac4c73dbea: Pulling fs layer
fdebdab8bd70: Pulling fs layer
de4c50052e70: Download complete
0347dcb76707: Download complete
0347dcb76707: Pull complete
fdebdab8bd70: Download complete
b3aa25c040eb: Download complete
55a95237d05e: Download complete
b2964fb1c339: Download complete
04795e9ec375: Download complete
60dd07915845: Download complete
8e2567281c84: Download complete
ff811290060a: Download complete
ff811290060a: Pull complete
60dd07915845: Pull complete
6d7fe3139aab: Download complete
f6401c83faed: Download complete
5654b802c6ab: Download complete
87a58e95f8aa: Download complete
e91105a42626: Download complete
failed to copy: httpReadSeeker: failed open: failed to do request: Get "http://192.168.0.11:5555/v2/nginxproxymanager/nginx-full/blobs/sha256:28c358a22b3fc329e51d8902b268b47c813c838a4317759a9486f1cc9e384450?ns=docker.io": dial tcp 192.168.0.11:5555: connect: connection refused