Develop UI for Email Template Editor

[Siddhanttimeline]

The backend work for the email template editor has been completed, and all necessary APIs are ready for integration. The UI team is tasked with developing a user-friendly interface for creating and editing email templates. This editor should allow users to edit the content of the email templates and manage predefined placeholders that are already implemented in the backend.

1. Template Editing: The editor should allow users to modify the content of email templates.
2. Placeholder Management: Each email template will have a set of predefined placeholders. Users can remove placeholders but cannot add new ones. Placeholder management must adhere to backend constraints (i.e., no additional placeholders can be added beyond the predefined set).
3. Placeholder Descriptions: The API will return descriptions for each placeholder. These descriptions must be displayed while users edit the template to help them understand the purpose of each placeholder.
4. Reset to Original: A "Reset" option must be implemented to revert the template to its original form that restores the default template and placeholders.
5. Validation: Show a meaningful message when template validation fails.