Add cached memory to memory section

[KosumovicDenis]

Add Cached Memory Usage and Customization Options

I'm excited to share this pull request, which aims to enhance memory monitoring by including cached memory usage.

Changes:

• Displayed Memory Usage: Now includes cached memory.
• Memory Usage Graph: Incorporates cached memory.
• Settings:
  • Added an option to toggle cached memory display.
  • Added a color picker for cached memory.