sanitize BUILD_TAG for JePL

[vykozlov]

If there are a few commits one after each other, simultaneous Jenkins Jobs are triggered but with the same (?) JePL container name by default. Since JePL allows to define a container name "manually", one can define it as e.g. $BUILD_TAG, which is always different in Jenkins. However, if the branch name is e.g. "feature/my-new-code", the "/" symbol is not sanitized by JePL and container name contains "/", therefore failing to create due to "Invalid container name".

One approach: update JePL

Another: change how the container name is defined, e.g. SQA_CONTAINER_NAME, but it has to be passed from parent to child Jenkins job.