qmlformat: Allow specifying alternative location for .qmlformat.ini

Currently, qmlformat seems to look for .qmlformat.ini files in the directory of each *.qml file. Also, settings from a parent directory are propagated to its subdirectories, until overridden by another .qmlformat.ini file in the subdir. If no .qmlformat.ini file is found in the directory of the *.qml file or its parent directories, then the "default" settings are used. (Assuming no command line options are specified)

Suggestion

Provide the ability to specify the path to an external settings file to replace the "default" settings.