Status indicator for pack and unpack

[bmicklea]

Describe the problem you're trying to solve
It's unclear when you do a pack or unpack how long it will take or whether it's even still working. For large models and datasets there could be quite a long delay in building the ModelKit.

Describe the solution you'd like
Some kind of status update including a description of what it's doing at various stages / steps.

Describe alternatives you've considered
n/a

Additional context
none