JavaDoc cautionary hint for `safeMapGet`.#933

sebastian-peter merged 4 commits intodevie3-institute/PowerSystemDataModel:devfrom

ms/#828-throw-exception-instead-of-questionable-`EntitySource.safeMapGet`ie3-institute/PowerSystemDataModel:ms/#828-throw-exception-instead-of-questionable-`EntitySource.safeMapGet`Copy head branch name to clipboard