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.h

@@ -17,19 +17,19 @@ class ScriptEditor : public GUI::TextEditor {
 public:
     virtual ~ScriptEditor() = default;
 
-    void new_script_with_temp_name(DeprecatedString);
+    void new_script_with_temp_name(ByteString);
     ErrorOr<void> open_script_from_file(LexicalPath const&);
 
     ErrorOr<bool> save();
     ErrorOr<bool> save_as();
     ErrorOr<bool> attempt_to_close();
 
-    DeprecatedString const& path() const { return m_path; }
+    ByteString const& path() const { return m_path; }
 
 private:
     ScriptEditor();
 
-    DeprecatedString m_path;
+    ByteString m_path;
 };
 
 }