This addresses #1051. There is one more pull request that needs to be completed/merged (for `CompositeTagHelperDescriptorResolver` and friends). After that, runtime should work!
- Updated `ScriptTagHelper` and `LinkTagHelper` to maintain their quotes on generated script tags.
- Removed `TagHelperOutputExtensions`. It's no longer needed.
- We no longer string replace quotes directly. We rely on encoding and the initial representation of an attribute to ensure quotes don't break generated attributes.
- Updated tests.