Ability to create a new pack instead of selecting from existing packs

[m4dcoder]

Currently when creating a new workflow, the pack selection can only be one of the existing packs. It will be nice to be able to specify a new pack and then create the new pack and related files for it.

[bmomberger-bitovi]

Putting the "Design needed" label on this so we can work out what the UX flow would be. Likely not that difficult: e.g. a + button that pops a free text field and an "Add" button into the form.