Everywhere: Rename {Deprecated => Byte}String

This commit un-deprecates DeprecatedString, and repurposes it as a byte
string.
As the null state has already been removed, there are no other
particularly hairy blockers in repurposing this type as a byte string
(what it _really_ is).

This commit is auto-generated:
  $ xs=$(ack -l \bDeprecatedString\b\|deprecated_string AK Userland \
    Meta Ports Ladybird Tests Kernel)
  $ perl -pie 's/\bDeprecatedString\b/ByteString/g;
    s/deprecated_string/byte_string/g' $xs
  $ clang-format --style=file -i \
    $(git diff --name-only | grep \.cpp\|\.h)
  $ gn format $(git ls-files '*.gn' '*.gni')

Userland/Libraries/LibWeb/HTML/NavigationHistoryEntry.cpp

@@ -65,7 +65,7 @@ WebIDL::ExceptionOr<Optional<String>> NavigationHistoryEntry::url() const
         return OptionalNone {};
 
     // 5. Return she's URL, serialized.
-    return TRY_OR_THROW_OOM(vm(), String::from_deprecated_string(she->url.serialize()));
+    return TRY_OR_THROW_OOM(vm(), String::from_byte_string(she->url.serialize()));
 }
 
 // https://html.spec.whatwg.org/multipage/nav-history-apis.html#concept-navigationhistoryentry-key