Add missing data in quick start guide about required envs

[PoslinskiNet]

Short overview

Documentation is not completed. Anyone can't start the application only by following installation steps - it requires extra setup that is not mentioned in the project readme.

ToDo

• add proper section in quick start guide section about required envs for 1st start locally (for Stripe & S3)

Deadline

• Nice to have

Contact points

@typeWolffo

Notes

Alternative scenario could mean make those envs optional.