Request for Email Template Customization in Grafana Operator

[captainpro-eng]

We would like to request the ability to customize email templates within Grafana when using Grafana Operator. Currently, the default email notification templates are basic, and we would like to customize them to better fit our organization's branding and requirements.

Use Case:

We need to align Grafana email notifications with our corporate style guide, including specific branding, colors, and message formatting.
We need the flexibility to modify alert messages based on the severity, context, and specific variables in the alert.
Benefits:

Allows for better integration of Grafana notifications within our enterprise system.
Provides a more user-friendly and consistent notification experience for our teams.
Enhances the flexibility of Grafana Operator in managing Grafana configurations.

[theSuess]

We're already tracking this in #1736 and there is a PR in the works in #1775