[CircleEditor] Refactoring structure and codes

[llFreetimell]

What?

Let's refactor overall structure and source codes for CircleEditor.

Why?

• To improve performance
• To improve static analysis score
• To improve readability and maintainability
  • Remove source codes which are not related with editing circle file
  • Rename variable and functions
• To fix bugs

Draft

• #1454

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TODO Items

• [ ] Minimize duplicated source codes
  • [ ] Reposition external source codes
  • [ ] Remove not modified source codes from our own codes
• [ ] Remove source codes which are not related with editing circle file
• [ ] Rename variable and functions which have unclear names
• [ ] Improve performance
  • [ ] Substitute opening a file with rendering graph after editing
  • [ ] Do not change when before and after are same
• [ ] Clean codes
  • [ ] Separate value validation function when save
• [ ] Fix bugs
  • [ ] Edit custom attribute --> Ctrl+z --> arrows are dismissed
  • [ ] BCQ(maybe some other operations too) attribute types are null
  • [ ] Custom options only supports few types
  • [ ] Even invalid attribute values are given, changes are generated