Allow applications to trigger HTTP/2 stream resets while using
NIOHTTPTypesHTTP2's codecs
### Motivation:
Resetting streams with specific error codes is required by some
applications such as those implementing the CONNECT method
(see https://datatracker.ietf.org/doc/html/rfc9113#section-8.5-8).
Unfortunately, the HTTP2ToHTTP codecs don't expose this capability to
applications.
### Modifications:
Introduce an outbound user event applications can trigger when needing
to reset an HTTP/2 stream.
### Result:
Now applications can trigger HTTP/2 stream resets while using the codecs
provided by NIOHTTPTypesHTTP2
### Motivation:
To migrate to GitHub actions and centralised infrastructure.
### Modifications:
Changes of note:
* Adopt swift-format using rules from SwiftNIO
* Remove scripts and docker files which are no longer needed
### Result:
Feature parity with old CI.
* Add HTTP types adapter for SwiftNIO
* swiftformat
* Guard on Swift 5.8
* Review comments
* Update swift-http-types to 0.1.1
* Update swift-http-types to 1.0.0
* Review feedback
* Review feedback
* Bump minimum Swift version to 5.7.1
* Allow Host in any order
