Change 'Editor' to 'creator'

[lauracumming]

Task Description

The level editor is an 'editor' but it is also where people 'create' levels and this is more what it should be described to users as.

Acceptance Criteria

• Amend text in pop-up from editor to creator
• Check no further changes are needed elsewhere

Good Places to Start - please add @faucomte97 @SKairinos

Link to a specific directory / file / line that would be a good place to
start working on this task. The more specific the better.