Create project from template

[zdenek-musil]

Is your feature request related to a problem? Please describe.
When creating new projects, it is always necessary to manually create the same or similar structure of sections and tasks. This process is time-consuming and prone to errors or omissions of important tasks. Currently, there is no option to automatically create a project with a predefined structure.

Describe the solution you'd like
Implement a project template functionality that will allow:

Create and manage predefined project templates
Each template will contain:

Section structure (e.g., "Preparation", "Development", "Testing", "Documentation")
List of predefined tasks in each section
Ability to define basic task attributes (priority, estimated time)

When creating a new project, option to select a template and automatically create a project with the entire predefined structure
Ability to modify the generated structure according to specific project needs

Describe alternatives you've considered
Manual copying of structure from existing projects - time-consuming and impractical
Export/import of structure using CSV/JSON - less user-friendly
Creating a checklist for manual setup - still requires manual work

Additional context
Feature should be available for all project types
Template management is important (creation, editing, deletion)
It would be beneficial to enable template categorization by project type
The ability to share templates between teams would be useful