Add per app version helpers

[bryanhelmig]

Adds this cool little feature:

➜  example-app zapier invite
The invitees on your app "Example App" listed below.

Invitees not found. Try adding one with `zapier invite user@example.com`.

You can invite users to this app more broadly by sharing this URL:

  http://localhost:8000/platform/public-invite/2/d33ec180b5796fa90744882c2a3da43b/

You can invite users to each version:

  1.0.0: http://localhost:8000/platform/public-invite/2/1137/b2ddf03f3afba9494ba21cffa4173c48/
  1.0.1: http://localhost:8000/platform/public-invite/2/1138/eb15069071c89e5a6593d7fee7a1f3ac/

[xavdid]

sweet!

I apparently can't comment on lines that weren't modified, but i'd change the original invite message (_access.js#78) to:

You can invite users to all versions of this app (current and future) using this URL:

to help differentiate why each section is different.

[xavdid]

you can revert this - we generate this file automatically when we do a release. Also, 8.0.1 is now listed twice

[xavdid]

@bryanhelmig is this still relevant? I'm closing out or merging old PRs as possible. We should close or merge this as appropriate!

[bryanhelmig]

No reason this can't merge as is, just forgot about it!