As historical romance series “Outlander” prepares to close its eight-season run next year, Starz has primed a new generation of talent to carry on the beloved franchise with prequel series “Outlander: Blood of My Blood.” And the cast of the new series is more than ready to tackle the challenge. Centering on the love story between the parents of the flagship series’ Jamie and Claire — roles made famous by Sam Heughan and Caitriona Balfe — “Blood of my Blood” introduces Harriet Slater and Jamie