(feature) webhook alerts

[pro1code1hack]

Please describe your changes using the checklist below.

Self-hosted support

• Your feature is implemented for the selfhosted version of Swetrix
• This PR only updates the production code (e.g. paddle webhooks, CAPTCHA, blog, etc.)

Database migrations

• Clickhouse / MySQL migrations added for this PR
• No table schemas changed in this PR

Documentation

• You have updated the documentation according to your PR
• This PR did not change any publicly documented endpoints

How to test this feature:

• Insert the following data into the db

mysql> select * from users_webhooks;
+--------------------------------------+--------------------------------------+------+-------------------------------+----------------------------+----------------------------+
| id                                   | userId                               | name | url                           | createdAt                  | updatedAt                  |
+--------------------------------------+--------------------------------------+------+-------------------------------+----------------------------+----------------------------+
| f04816b4-7516-44ba-9fb3-82e065667785 | c6df6997-80a9-4b27-9248-a15af0b97ca9 | Test | http://localhost:3000/webhook | 2024-07-11 21:12:51.266892 | 2024-07-12 20:05:35.460372 |
+--------------------------------------+--------------------------------------+------+-------------------------------+----------------------------+----------------------------+

• Create express JS server

const express = require('express');
const bodyParser = require('body-parser');
const app = express();
const port = 3000;

app.use(bodyParser.json());

app.post('/webhook', (req, res) => {
    console.log('Received webhook:', req.body);

    res.status(200).send('Webhook received');
});

app.listen(port, () => {
    console.log(`Webhook receiver listening at http://localhost:${port}`);
});

You should see the following output in the console:

 {
  event: 'user.alert.metrics',
  data: {
    alertName: 'Test Alert',
    projectName: 'Your awesome project',
    count: 0,
    queryMetric: 'page_views',
    queryCustomEvent: null,
    queryTime: '0'
  }
}

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