Move locales from public to private

private/moment-locales/af.js

private/moment-locales/ar-ma.js

private/moment-locales/ar-sa.js

private/moment-locales/ar-tn.js

private/moment-locales/ar.js

private/moment-locales/az.js

private/moment-locales/be.js

private/moment-locales/bg.js

private/moment-locales/bn.js

private/moment-locales/bo.js

private/moment-locales/br.js

private/moment-locales/bs.js

private/moment-locales/ca.js

private/moment-locales/cs.js

private/moment-locales/cv.js

private/moment-locales/cy.js

private/moment-locales/da.js

private/moment-locales/de-at.js

private/moment-locales/de.js

private/moment-locales/el.js