This commit removes the 'experimental_preconnect_link_header' site setting, and the 'preload_link_header' site setting, and introduces two new global settings: early_hint_header_mode and early_hint_header_name.
We don't actually send 103 Early Hint responses from Discourse. However, upstream proxies can be configured to cache a response header from the app and use that to send an Early Hint response to future clients.
- `early_hint_header_mode` specifies the mode for the early hint header. Can be nil (disabled), "preconnect" (lists just CDN domains) or "preload" (lists all assets).
- `early_hint_header_name` specifies which header name to use for the early hint. Defaults to "Link", but can be changed to support different proxy mechanisms.
1cc8c72a98