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/Scripting/Environments.cpp

@@ -308,7 +308,7 @@ bool EnvironmentSettingsObject::is_scripting_disabled() const
 }
 
 // https://html.spec.whatwg.org/multipage/webappapis.html#module-type-allowed
-bool EnvironmentSettingsObject::module_type_allowed(AK::DeprecatedString const& module_type) const
+bool EnvironmentSettingsObject::module_type_allowed(AK::ByteString const& module_type) const
 {
     // 1. If moduleType is not "javascript", "css", or "json", then return false.
     if (module_type != "javascript"sv && module_type != "css"sv && module_type != "json"sv)