This patch adds the [`doT`](https://npmjs.org/dot) template engine to `axe.imports`. This is required for a runtime localization (a WIP feature).

A lot of hackery was required to get this working, since `doT` doesn't expose a UMD wrapper that our build system supports. Rather than attempting to get our existing tooling to "unwrap" `doT`'s custom UMD, I've decided to save a lot of time/effort and just wrap it in an IIFE. There are likely 1,000,000s of variations of UMD in the wild and it's unreasonable for us to attempt to support them all. The added IIFE method works in cases where the code functions exactly the same regarless of enviroment (this does not include libraries like Axios). IMHO the only reasonable solution to this problem is to use a proper bundler for building `axe-core`.