feat: Implement `AchievementTile`

[apomalyn]

As a user, I want to see my unlocked achievements easily without opening the details

Requirements

• Implement a AchievementTile widget, that:
  • can be pressed
  • display:
  • the unlocked image
  • the name of the achievement
  • the current level unlocked if available

What needs to be done

• Under src/achievements/widgets implement an AchievementTile that shows:
  • the unlocked image:
  • if the image isn't available in the assets, try loading it from the API (URL to be determined)
  • the name of the achievement
  • the current level unlocked if available
  • have a VoidCallback onPressed parameter that will be called when the widget is pressed
• Update the AchievementsView grid to use the newly created AchievementTile

Design

AchievementTile wireframe


Dependencies

Child of #31

Depends on:

• 151