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/profile.cpp

@@ -38,7 +38,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     args_parser.add_option(Core::ArgsParser::Option {
         Core::ArgsParser::OptionArgumentMode::Required,
         "Enable tracking specific event type", nullptr, 't', "event_type",
-        [&](DeprecatedString event_type) {
+        [&](ByteString event_type) {
             seen_event_type_arg = true;
             if (event_type == "sample")
                 event_mask |= PERF_EVENT_SAMPLE;