Refactoring code before release

[sc420]

• Use operation name, not operation text
• Use same naming conventions for mocks: MockComponent
• Use getNodeById/getNodes something like that for singular/plural items
• Don't use upper case for types, just use normalCase
• Use ReadonlyMap, ReadonlySet whenever possible
• Use Stack instead Grid whenever possible
• Check if there're any linter errors
• Remove TODOs, replace with comments