Code review comment for ~jslarraz/review-tools:container-add-get-yaml

Add `get_yaml` function to base_container. This function will use ruamel.yaml to load a yaml file in the container and return the corresponding dictionary.

Using ruamel.yaml with `.allow_duplicate_keys = False` removes the need to perform this check separately.

A clean up has also been performed in sr_common using this new `get_yaml` function.