[Feature Request] Add Support for Notifications via Slack

[mstfknn]

It would be great to have an option to receive notifications from Wallos directly on Slack. This feature could enhance real-time monitoring and make it easier for teams to stay updated.

Feature Request:
1. Add Slack integration to Wallos.
2. Allow configuration of a Slack Webhook URL in the settings.
3. Send notifications for key events directly to a specified Slack channel.

Benefits:
• Improved team communication and collaboration.
• Timely updates for critical events.
• Increased flexibility for users who rely on Slack for notifications.

POST https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX
Content-type: application/json
{
    "text": "Danny Torrence left a 1 star review for your property.",
    "blocks": [
    	{
    		"type": "section",
    		"text": {
    			"type": "mrkdwn",
    			"text": "Danny Torrence left the following review for your property:"
    		}
    	},
    	{
    		"type": "section",
    		"block_id": "section567",
    		"text": {
    			"type": "mrkdwn",
    			"text": "<https://example.com|Overlook Hotel> \n :star: \n Doors had too many axe holes, guest in room 237 was far too rowdy, whole place felt stuck in the 1920s."
    		},
    		"accessory": {
    			"type": "image",
    			"image_url": "https://is5-ssl.mzstatic.com/image/thumb/Purple3/v4/d3/72/5c/d3725c8f-c642-5d69-1904-aa36e4297885/source/256x256bb.jpg",
    			"alt_text": "Haunted hotel image"
    		}
    	},
    	{
    		"type": "section",
    		"block_id": "section789",
    		"fields": [
    			{
    				"type": "mrkdwn",
    				"text": "*Average Rating*\n1.0"
    			}
    		]
    	}
    ]
}

[TheSander562]

I have it now setup with a regular webhook.

With additional header : ["Content-Type: application/json"]
And changed the subscriptions to keyname : text
But TEST notifications are working but the regular notifications are not with the following config:

{
	"blocks": [
		{
			"type": "header",
			"text": {
				"type": "plain_text",
				"text": ":money_with_wings: Er komt een nieuwe betaling aan voor {{subscription_name}} :money_with_wings:"
			}
		},
		{
			"type": "section",
			"fields": [
				{
					"type": "mrkdwn",
					"text": "*Over:*\n{{subscription_days_until_payment}}"
				},
				{
					"type": "mrkdwn",
					"text": "*Kosten:*\n{{subscription_currency}} {{subscription_price}}"
				}
			]
		},
		{
			"type": "section",
			"fields": [
				{
					"type": "mrkdwn",
					"text": "*Betaler:*\n<@U01KKNG75PE>"
				},
				{
					"type": "mrkdwn",
					"text": "*Meer info:*\n<{{subscription_url}}|klik hier>"
				}
			]
		}
	]
}

[mstfknn]

yes, I had the same problem