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/DevTools/SQLStudio/ScriptEditor.cpp

@@ -21,7 +21,7 @@ ScriptEditor::ScriptEditor()
     set_ruler_visible(true);
 }
 
-void ScriptEditor::new_script_with_temp_name(DeprecatedString name)
+void ScriptEditor::new_script_with_temp_name(ByteString name)
 {
     set_name(name);
 }
@@ -37,7 +37,7 @@ ErrorOr<void> ScriptEditor::open_script_from_file(LexicalPath const& file_path)
     return {};
 }
 
-static ErrorOr<void> save_text_to_file(StringView filename, DeprecatedString text)
+static ErrorOr<void> save_text_to_file(StringView filename, ByteString text)
 {
     auto file = TRY(Core::File::open(filename, Core::File::OpenMode::Write));