[FEATURE] Add Documentation Menu with Markdown Export for Database Documentation

[LuigimonSoft]

We need to enhance our application by adding a new menu item dedicated to documentation. This menu should provide an option to generate database documentation in Markdown format. When the user clicks on the "Markdown" option, a new window should open, allowing them to export the database documentation. The Markdown file should represent the documentation in a data dictionary format.

Requirements:

1. Add Documentation Menu:

   • Introduce a new menu item called "Documentation" in the application.
   • Under this menu, include an option labeled "Export as Markdown."

2. Generate Markdown Documentation:

   • On selecting "Export as Markdown," open a new window.
   • In this window, display a preview of the database documentation in Markdown format.
   • The Markdown should follow a data dictionary format, including:
     • Table Names: Each table should be clearly labeled.
     • Columns: For each table, list all the columns with details such as:
     • Column Name
     • Data Type
     • Constraints (e.g., Primary Key, Foreign Key, Unique)
     • Default Values (if any)
     • Nullable (yes/no)
     • Indexes: Include details of any indexes on the tables.
     • Relationships: Describe the relationships between tables, such as foreign key references.

3. Export Functionality:

   • Provide an "Export" button in the Markdown preview window.
   • On clicking "Export," the Markdown file should be downloaded to the user's machine.