Speed Up and Disable Fragment URL Provider by Default

[Nicholas-Westby]

I'm thinking the fragment URL provider should be an opt-in feature rather than an opt-out feature. Would be nice to figure out some way of elegantly handling the change so old projects don't automatically break.

Also, this provider can slow down performance significantly if developers try to get a URL outside of an Umbraco context (e.g., in an API controller). Umbraco seems to do it faster (I think)... maybe look into how Umbraco does it to see if that behavior can be replicated.