LibWeb: Implement generic boolean logic for media/supports queries

CSS Values 5 now defines a `<boolean-expr[]>` type that is used in place
of the bespoke grammar that previously existed for `@media` and
`@supports` queries. This commit implements some BooleanExpression
types to represent the nodes in a `<boolean-expr[]>`, and reimplements
`@media` and `@supports` queries using this.

The one part of this implementation I'm not convinced on is that the
`evaluate()` methods take a `HTML::Window*`. This is a compromise
because `@media` requires a Window, and `@supports` does not require
anything at all. As more users of `<boolean-expr[]>` get implemented in
the future, it will become clear if this is sufficient, or if we need
to do something smarter.

As a bonus, this actually improves our serialization of media queries!

Libraries/LibWeb/CMakeLists.txt

@@ -55,6 +55,7 @@ set(SOURCES
     Crypto/SubtleCrypto.cpp
     CSS/Angle.cpp
     CSS/AnimationEvent.cpp
+    CSS/BooleanExpression.cpp
     CSS/CalculatedOr.cpp
     CSS/Clip.cpp
     CSS/CountersSet.cpp