Added a line in the .gitattributes file to enforce LF line endings for Dockerfile. This is to avoid any potential issues with line endings when working cross-platform, ensuring that Dockerfile will consistently use LF regardless of the environment.
Adjusted Docker `FROM` statement in Dockerfile and removed app-icon installation. Updated SMAPI installer command to search in the correct directory. Added .gitattributes file to ensure line-endings are consistent by converting all CRLF to LF.