Support for external Apprise API server

[Fooughhy]

Version and OS
0.51.4, running in Podman on Ubuntu 24.10 (arm64).

Is your feature request related to a problem? Please describe.
To centralize credentials management, I have set up an (Apprise API)[https://github.com/caronc/apprise-api] server on my Orange Pi 5 Plus at home. This is an official API for Apprise, owned by the same user.

When using this, I do not have to save the credentials for my various notification endpoints (e.g. Gmail) in each local service that needs to use them. I save the credentials in Apprise, and then have other services use the Apprise API to send the notifications without credentials.

But this means the URL for sending notifications is not an Apprise URL (e.g. "mailto://..."). But instead a normal FQDN (or just IP).
Like: 192.168.0.1:8000/notify/<config_id>

From what I can see, changedetection.io does not support any external Apprise server. And it is currently not even possible to save the notification configuration if you don't have a valid Apprise URL format, so an IP address will not work.

Describe the solution you'd like
I would like for changedetection.io to support an external Apprise server, though Apprise API.

Describe the use-case and give concrete real-world examples
Attach any HTML/JSON, give links to sites, screenshots etc, we are not mind readers

Additional context
Add any other context or screenshots about the feature request here.

[dgtlmoon]

Isnt this simply solved by using

get://localhost-apprise-server:8000/notify
or
gets://localhost-apprise-server:8000/notify

or

post://localhost-apprise-server:8000/notify
or
posts://localhost-apprise-server:8000/notify

as the notification url?
?

[Fooughhy]

Hmm, that could work. Normally Apprise seems to require "multipart/form-data" for requests for their API. But I can do this:
curl -X POST -H "Content-Type: application/json" -d '{"tag":"<valid_tag>","body":"hello","action":""}' "http://192.168.0.25:8000/notify/<config_id>"

And in my mind this basically converts to:
"Notification URL List": Apprise - post://192.168.0.X:XXXX/notify/<config_id>
"Notification Title": hello
"Notification Body":

{
    "tag": "<valid_tag",
    "body": "hello",
    "action": ""
}

But it fails in Apprise due to "400 Bad Request". It seems the URL becomes cluttered with many parameters:

2026-01-04 10:31:39,368 [WARNING] django: NOTIFY - - Payload lacks minimum requirements using KEY: <config_id>
2026-01-04 10:31:39,369 [WARNING] django.request: Bad Request: /notify/<config_id>
10.10.10.1 - - [04/Jan/2026:17:31:39 +0100] "POST /notify/<config_id>?avatar_url=https%3A%2F%2Fraw.githubusercontent.com%2Fdgtlmoon%2Fchangedetection.io%2Fmaster%2Fchangngedetectionio%2Fstatic%2Fimages%2Favatar-256x256.png&format=html HTTP/1.1" 400 34 "-" "python-requests/2.32.5"
2026/01/04 17:31:39 [info] 43#43: *1236 client 10.10.10.1 closed keepalive connection

[dgtlmoon]

10.10.10.1 - - [04/Jan/2026:17:31:39 +0100] "POST /notify/<config_id>?

You are literally sending the word "<config_id">, shouldnt it be some UUID or other?