Update README.md

[Universe-stack]

I added checkmarks at appropriate places to ease reading. I also adjusted some sentences for better grammatical meaning.

The essence of these actions is to improve user experience and customer understanding.

Definition of Ready

• [ x] I am happy with the code
• [ x] Short description of the feature/issue is added in the pr description
• [ x] PR is linked to the corresponding user story
• [ x] Acceptance criteria are met
• [ x] All open todos and follow ups are defined in a new ticket and justified
• [x ] Deviations from the acceptance criteria and design are agreed with the PO and documented.
• [x ] No debug or dead code
• [ x] My code has no repetitions
• [x ] Critical parts are tested automatically
• [ x] Where possible E2E tests are implemented
• [x ] Documentation/examples are up-to-date
• [ x] All non-functional requirements are met
• [ x] Functionality of the acceptance criteria is checked manually on the dev system.