Yat,
Unfortunately, given we now allow for multiple media files to be applied to a cue, "Media Templates" can no longer be created. If you are inserting videos into the script and want them to dissolve in, you need to set the transition in the Cue & Page options to Dissolve. If you are inserting multiple videos, if you select all of those Cues, you can apply this transition to all of them at the same time.
Hope this helps.