Closescoder/internal#674

Description:

• Throttle notifications to template admins: send no more than one notification per 7 days.
• Throttle notifications to template version author: send no more than one notification per 1 day.

Note:
It's done per template:

CREATETABLEtemplate_prebuild_notification_cooldowns (template_id UUIDNOT NULL,notification_typeTEXTNOT NULL,last_notification_sentTIMESTAMPTZNOT NULL,PRIMARY KEY (template_id, notification_type));

We can have multiple broken templates - in this case Template Admins will get one notification per template per 7 days.
I think it shouldn't be more than few notifications per week.

If it's still too noisy - we can consider making cooldowns global instead of template-specific. It should be enough to removetemplate_id field.