analyze: Add times in seconds for Activating and Activated in tooltip

Print the times in seconds in the tooltip to remove the need to count
and trying to follow the lines in the svg diagram in order to see at
what times these events happen.

src/analyze/analyze-plot.c

@@ -168,7 +168,9 @@ static void plot_tooltip(const UnitTimes *ut) {
         assert(ut->name);
 
         svg("%s:\n", ut->name);
-
+        svg("Activating: %"PRI_USEC".%.3"PRI_USEC"\n", ut->activating / USEC_PER_SEC, ut->activating % USEC_PER_SEC);
+        svg("Activated: %"PRI_USEC".%.3"PRI_USEC"\n", ut->activated / USEC_PER_SEC, ut->activated % USEC_PER_SEC);
+        
         UnitDependency i;
         FOREACH_ARGUMENT(i, UNIT_AFTER, UNIT_BEFORE, UNIT_REQUIRES, UNIT_REQUISITE, UNIT_WANTS, UNIT_CONFLICTS, UNIT_UPHOLDS)
                 if (!strv_isempty(ut->deps[i])) {