Added webhook support for sending Notification results

[caronc]

Description:

Related issue (if applicable): refs #101

Note: This change will not work until Apprise v1.6.0 is released as it includes changes to help assist with this enhancement.

Define the APPRISE_WEBHOOK_URL to be the full URL you wish to notify after each call to the Apprise API is made.

Your URL can contain the following parameters to allow you to configure some internal switches.

The following are example URLs:

• http://example.com/webhook/: A simple URL to call on each notification sent
• https://user:pass@example.com/webhook?cto=6&verify=no: A user/password authentication is applied to https://example.com/webhook .
  • the cto updates to connect timeout from the default 4.0 (seconds), to 6.0 (seconds).
  • the verify switch tells Apprise to not verify the SSL Certificate against the Certificate Authority (CA). This is useful for self generated certificates.

Payload

The payload sent to the webhook end point looks like:

{
   "source": "<remote user ip address>",
   "status": 0,
   "output": "log output",
 }

The status is 0 on success and 1 if a failure.

Checklist

• [ ] The code change is tested and works locally.
• [ ] There is no commented out code in this PR.
• [ ] No lint errors (use flake8)
• [ ] Tests added

[codecov-commenter]

Codecov Report

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Files	Coverage Δ
apprise_api/api/views.py	100.00% <100.00%> (+0.57%)	:arrow_up:
apprise_api/api/utils.py	86.36% <83.33%> (+18.63%)	:arrow_up:

... and 10 files with indirect coverage changes

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