Blocking JS initialization logic

[ValarDragon]

There is a lot of frontend logic that is causing blocking behaviors for further network requests, leading to very high cache-hit load times.

For instance if you do a performance profile and network profile of the FE cache hit loads, we see very large initialization logic times. Here is a screenshot of one such one of these, which is taking 130ms.

This blocks further network requests, which in turn have a large amount of blocking behavior. We should get this JS logic to be non-blocking for more page load network requests.