Stack view part 1

[Resaki1]

Description

Implemented the first part of the new stack view design. The features to navigate between stacks and to maximize a card are still missing, but since I'm going on vacation soon I thought it'd be better to merge this first :)

Changelog

• New stack view design
  • Colored border around screen
  • blurred background has color now
  • header is centered and bigger
  • stack parent note is bigger and stays on screen when scrolling the other notes
  • Me-chip for own cards
  • new note action buttons and improved layout
  • lowered saturation and increased lightness of accent color in dark mode for better readability
• refactored the menu bar buttons to be reusable in other parts of the application (i.e., the stack view)

Checklist

• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] The light- and dark-theme are both supported and tested
• [x] The design was implemented and is responsive for all devices and screen sizes
• [x] The application was tested in the most commonly used browsers (e.g. Chrome, Firefox, Safari)

Visual Changes