[IMPROVEMENT] Better Small Window Size Handling

[Meteony]

Please confirm these before moving forward.

• I have searched for my feature proposal and have not found a work-in-progress/duplicate/resolved/discarded issue.
• This improvement refers to an existing feature. If you want to suggest a new feature, please use this template.
• This improvement is not a bug. If you want to report a bug, please use this template.

Describe the improvement

There are a few nit-picks that I'm having as to how UniGetUI renders itself at smaller window sizes.

For example:

• Columns aren't sized to fit. Sources / version IDs should probably have more space reserved.

  • Avalonia:
  
  • WinUI 3:
  

• A few buttons in the menu bar don't fit into a smaller window width. One potential solution is to swap to some more condensed, text-less variants once window width hits some specific threshold.
  

• Card views can have dynamic sizing as well. Currently there's wasted space on the right.

  • Avalonia:
    

    

  • WinUI 3: