[INTERNAL] Add path to yaml_reader singleton id
[INTERNAL] Add path to yaml_reader singleton id

This allows to have two different yaml_reader instances **if path is
different**. Otherwise, the factory would always return the same instance,
no matter the path.

Example:

yaml_reader_1 = yaml_reader_factory.yaml_reader('/some/yaml/file/path')
yaml_reader_2 = yaml_reader_factory.yaml_reader('/another/yaml/file/path')
yaml_reader_3 = yaml_reader_factory.yaml_reader('/some/yaml/file/path')

We don't want the same instance for yaml_reader_1 and yaml_reader_2, but
yaml_reader_3 should be the same instance than yaml_reader_1.

aleasoluciones/infcommon,aleasoluciones/infcommon