This implements the pitch names for VST3.

• add a program list with one single program
• associate this program list with the root unit
• update the program name on file load
• update the pitch names on receiving the sfz description
  by priority, it's the key label if it exists, otherwise the keyswitch label
  (the keyswitch names should be also implemented in a secondary interface IKeyswitchController. it appears that very few hosts support this currently. see also https://forums.steinberg.net/t/changing-the-keyswitches/715964)