[FEATURE] App Developer Account and Allow Private App Installations in any Workspace

**Is your feature request related to a problem? Please describe.**
No

**Describe the solution you'd like**
Allow private app developers to have a developer account. Then allow us to create private integrations that can be installed on any pipedream account.

**Do you have a workaround?**
No per our discussion in Slack

**Comparable features in other tools?**
Zapier app developers can invite people to a private unpublished integration and revoke access via email addresses.
Make allows app developer permissions which lets me go in their workspace and install my private app.

**Additional context**
A bonus would be one time share links. This is an issue on Make if people get a hold of our published share link.

Icing on the Cake: Allow a "publicly visible private app." So users see a padlock on the app icon. If they want that private app, then they pay and offer up various payment gateways like Stripe/Paypal to the developer or have the payment come direct from Pipedream to the developer. This would motivate private app developers so we can be rewarded for our time to build all the endpoints for apps that don't exist yet. It's also important to include the origin App in a tagline that shows up in your app search. So if people are looking for Slack and you haven' built that, then a private app will show up with the lock icon with the tagline that it is a private Slack integration. Additionally, dunning is needed so if a direct payment gateway is used versus payment from Pipedream to a developer.