piano: refactoring and improvement (#302)

- Refactored source code;
- Added Spanish translation;
- Updated UX / UI;
- Updated keyboard layout (fix #25);
- Added keymap configuration via separate binary file.

Reviewed-on: #302
Reviewed-by: Mikhail Frolov <mixa.frolov2003@gmail.com>
Reviewed-by: Max Logaev <maxlogaev@proton.me>
Co-authored-by: Burer <burer@kolibrios.org>
Co-authored-by: Doczom <mixa.frolov2003@gmail.com>
Co-authored-by: qullarwee <unknown@domain.local>
Co-committed-by: Burer <burer@kolibrios.org>

data/Tupfile.lua

@@ -532,6 +532,7 @@ tup.append_table(img_files, {
  {"MEDIA/MP3INFO", VAR_PROGS .. "/media/mp3info/mp3info"},
  {"MEDIA/PALITRA", VAR_PROGS .. "/media/palitra/trunk/palitra"},
  {"MEDIA/PIANO", VAR_PROGS .. "/media/piano/piano"},
+ {"MEDIA/PIANO.MAP", VAR_PROGS .. "/media/piano/piano.map"},
  {"MEDIA/STARTMUS", VAR_PROGS .. "/media/startmus/trunk/STARTMUS"},
  {"NETWORK/PING", VAR_PROGS .. "/network/ping/ping"},
  {"NETWORK/NETCFG", VAR_PROGS .. "/network/netcfg/netcfg"},