Feature Request: Add chord progressions

[tithrion]

Is your feature request related to a problem? Please describe.
Follow up to Feature request: Ability to add chords and progressions to sequencer patterns
Chords already implemented in Vangelis by @riban.
As proposed by @riban, I add separate FRs for progressions and beats/rhythms

Describe the solution you'd like
The ability to add chord progressions like in other sequencers (i.e. ardour media pack)
The initial idea was to have a context menu from which to choose via sublevels chords, progressions, beats to insert in zynpad in a pattern or track.
In this case we'd concentrate on the implementation of the progressions

Describe alternatives you've considered
One could copy a set of midi files of interest to the capture dir and import from there, but a direct availability and selectability would ease up things a lot and besides preventing the capture dir from being cluttered.

Additional context
As example, a Screenshot from ardour integration: