feat: Add a webhook integration

[ivanovyordan]

What kind of change does this PR introduce?

Feature

Why was this change needed?

This integration allows custom endpoints like n8n and Zapier.
Please checl issue #321 for more information.

Other information:

This integration also allows you to add a JSON path from the response, which enables posting comments to you webhook posts.

I didn't add authentication as the UI became too cluttered.

Checklist:

Put a "X" in the boxes below to indicate you have followed the checklist;

• I have read the CONTRIBUTING guide.
• I checked that there were not similar issues or PRs already open for this.
• This PR fixes just ONE issue (do not include multiple issues or types of change in the same PR) For example, don't try and fix a UI issue and include new dependencies in the same PR.

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