Hm. Yeah, survival seems like a reasonable choice for crafting webs. Lore might work too, or Craftsmanship. Really depends on what sort of flavor you want to go with for the character.
And do remember, one of the options for Echoes of the Beast is a single extra skill trapping - though that defaults to being usable in both human and shifted forms, which might not be appropriate for webbing.
If you want a standalone power for webbing, I'd say it'd be -1 refresh, and provide a basic (non-combat) webbing power, requiring a few minutes of preparation to create webs of reasonable size and effectiveness, and provide a +2 bonus to whatever the appropriate skill check is for crafting stuff out of spiderwebs. You'll also want to work out the values for various related checks - such as how hard it would be for someone to break out after you wrapped them up in webbing, or what sort of defense / armor / stress capacity / stealth value a webbing across a hallway might have. This sort of thing is up to your GM, and may need to be adjusted if the power proves to be, in actual use, either too strong or too weak.