Configurable support for static resource encodings

The new EncodedResourceResolver is a generalized version of
GzipResourceResolver that can be configured to support different
content codings, by "br" and "gzip".

GzipResourceResolver is now deprecated.

Issue: SPR-16381

spring-webflux/src/test/resources/org/springframework/web/reactive/resource/test/foo-e36d2e05253c6c7085a91522ce43a0b4.css

@@ -1 +0,0 @@
-h1 { color:red; }