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/Utilities/cpp-preprocessor.cpp

@@ -21,7 +21,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
     auto file = TRY(Core::File::open(path, Core::File::OpenMode::Read));
     auto content = TRY(file->read_until_eof());
-    DeprecatedString name = LexicalPath::basename(path);
+    ByteString name = LexicalPath::basename(path);
     Cpp::Preprocessor cpp(name, StringView { content });
     auto tokens = cpp.process_and_lex();
 
@@ -31,13 +31,13 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
             if (definition.value.parameters.is_empty())
                 outln("{}: {}", definition.key, definition.value.value);
             else
-                outln("{}({}): {}", definition.key, DeprecatedString::join(',', definition.value.parameters), definition.value.value);
+                outln("{}({}): {}", definition.key, ByteString::join(',', definition.value.parameters), definition.value.value);
         }
         outln("");
     }
 
     for (auto& token : tokens) {
-        outln("{}", token.to_deprecated_string());
+        outln("{}", token.to_byte_string());
     }
 
     return 0;