Refactor BuildTab UI and improve job management functionality

[gcbaptista]

This PR refactors the BuildTab UI and enhances the job management functionality in the village building system. The main changes include:

1. UI Improvements:

   • Moved job management buttons (Top, Up, Down, Bottom, Delete, Delete All) from the context menu to the bottom of the JobsGrid for better visibility and ease of use.
   • Reorganized the layout of the BuildTab for a more effecient and intuitive user experience.

2. Functionality Enhancements:

   • Added null checks in job management methods (Up, Down, Top, Bottom, Delete) to prevent actions on unselected items.
   • Improved error handling and user feedback for various operations.

These changes aim to improve the user experience when managing building jobs and provide a more robust and error-resistant implementation of the building management system.

[vinaghost]

can you use "is null"?

[vinaghost]

is there any special reason for place them in bottom instead together with import and export buttons ?

[vinaghost]

check my comment on .xaml and viewmodel file