Realtime Database to handle concurrent webhooks

[leomp12]

Is your feature request related to a problem? Please describe.
E-Com Plus and integrated solutions webhooks may occur almost at the same time, and it comes with some problems to process status changes and other flows.

Describe the solution you'd like
Start using Firebase Realtime Database in place of Firestore to deal with some realtime data, eg request limits and webhooks queuing. Firestore should still be used to the other (majority) data.

Describe alternatives you've considered
Cloud Run #138

Additional context
More related to ERPs integrations.

[leomp12]

see https://github.com/ecomplus/app-bling-erp/blob/master/functions/routes/ecom/webhook.js

[leomp12]

👉🏾 #138