[Ads] Make asynchronous + return promise

[galadhremmin]

Running Google Ads synchronously slows down the entire website as we become dependent on ads materialization. By shifting to an async model, we have the potential to speed things up significantly sitewide.

https://github.com/galadhremmin/Parf-Edhellen/blob/35e6cc9d4bc2f8cdd7d27c3035ecb8f8ea1b4d45/src/resources/assets/ts/ads.ts#L67