Export and import / merge chains

[riban-bw]

Is your feature request related to a problem? Please describe.
Sometimes you create the perfect chain. The guitar simulator is just right with the reverb and eq you love. You want to reuse this in other snapshots.

Describe the solution you'd like
Ability to export a snapshot that only includes the selected chain. This could be a option in the chain options menu.
Ability to import a snapshot and merge it with the existing model. This could be an option in a load snapshot sub-menu.
The merge should create a new chain and processors and configure them. It should replace existing single instance engines.

Describe alternatives you've considered
Write down all your settings and put them in a dusty old book.

Additional context
This can be used for templates of chains.

[riban-bw]

I have started to develop a solution in branch feature/export_chain. The export is working (but may need refining). Next I need to do the import / merge.

[riban-bw]

This is now implemented in vangelis, ready for testing. The workflow is:

Export a single chain

• Navigate to chain options menu.
• Select "Export chain...".
• Select bank.
• Enter a name for the snapshot.
• If duplicate file, confirm save.
  A snapshot is saved with just the single chain including its mixer and MIDI binding config.

Merge/import chains

• Navigate to the snapshot view and select the snapshot to import.
• From the context menu, select "Load Merge Chains".
  The following elements will be merged with the current config:
• Each chain within the snapshot:
  • Title
  • Next available mixer channel will be assigned
  • MIDI channel
  • Index of last accessed processor (doesn't seem to work)
  • Processors in chain (assigned next available processor ids)
  • Position of fader within chain (can't test due to issue 1275)
• zs3-0:
  • Processor configuration (remapped to new processor ids)
  • Mixer strip controls but not MIDI binding
  • Chain configuration: audio/midi in/out, transpose/keyrange, midi binding, etc.