Add hosting.de provider. To use dynamic DNS you have to create a DDNS
host with a separate DDNS user.
Note: As of 2023-01-17 hosting.de does not work with wget which will
fail with `400: Bad Request` (it will work with `--auth-no-challenge`).
You should use curl instead. I have reported that to the provider.
Signed-off-by: Benjamin Drung <bdrung@bdrung.de>
