* feat: FloodFill Algorithm with iterative approach
- nested class Point: helper class, represents point in 2D field (x,y)
- shouldSkipPixel method: helper method to validate point
- floodFill method: iterative version of floodFill, uses Queue to add and poll Points and change it color if allowed
* feat: tests for IterativeFloodFill
-same tests as for normal floodFill and test for a big image
* docs: add link to floodFill algorithm
* codeStyle fix
* tests: add tests for edge cases
* codeStyle fix
* codeStyle fix
* codeStyle fix
* refactor: reorganize structure and add JavaDoc
- Move private methods after public methods for better readability
- Add class-level JavaDoc documentation with algorithm description and links to references
