Add some color tag system to the piano roll notes.

### Enhancement Summary
Hi, I was watching some intonalist songs, and kept thinking about the whole pure intonation versus equal temperament and other tuning systems.
One issue most tuning systems is that not one is perfect.
But I keep thinking it should be possible to detune and tune every individual note or scale or all the notes in the same note in the scale to different ratios o even to arbitrarily tuning.

#### Justification
It's very hard with current lmms to even think of making every note to be in a diferent individual tuning.

#### Mockup
Make some kind of tag system to the piano roll notes, using diferent colors as visual tags for the notes, with every tag (color) to have some common properties, like a diferent tuning.
It could be added to the piano roll the same way the other note properties have a drop list button where you can select the color property you draw with the pencil tool.
There could be also another button next to it that will create a small pop up window to edit the color (tag) properties.
It could work very similarly to how you add or delete patterns in FL works, very similar to the chord or scale drop list button.

Start by locating the piano roll implementation and the existing note-property drop-down controls. Review how notes and patterns currently store editable properties, then determine the scope for color tags and per-tag tuning data. Done should include a defined interaction for creating, selecting, and editing tags, plus support for applying different tuning values to notes.

Written by the indexing model from the issue text.