🎨 [Reminder Email Template] When a user wants to send a reminder email for unpaid invoice, a template should be provided.

[Salemukuri]

Is your feature request related to a problem? Please describe.
To enhance the user experience and improve efficiency in sending reminder emails for unpaid invoices, it is crucial to provide an email template feature that offers convenience and customization options.

Describe the solution you'd like
Incorporate an email template feature with customization and user-created template capabilities.

Prototypes/designs

Additional context
This feature is dependent on implementation of #68