use fetch instead of jquery ajax

[timomayer]

https://developer.telerik.com/featured/fetch-modern-async-server-calls/
with an optional polyfill for older browsers: https://github.com/github/fetch

when we get rid of jQuery dependency in the condLoader we can use it in more projects and jQuery can be a dependecy we load with the conditional loader - much more flexibility.

lets have a look at https://github.com/jhabdas/fetch-inject especially for performance

[davelosert]

Just fyi: I wrote a jQuery Fetch adapter in one of our projects - I wanted to publish it since a while but never came around. Bascially it's a much smaller polyfill as no additional logic for netowrk requests is involved as long as you already have jQuery embedded in your page.

I'll try to release it this weekend and can reference it here if you'd like.

[timomayer]

@davelosert thanks! as said i prefer to get rid of the jQuery dependecy with using fetch to be more library independant and improve performance due to make conditionalLoader initialization possible without jQuery has to be loaded but you are right we have to compare the size of the polyfills needed without jquery (fetch, promise, ...) with a jQuery version.