Parallel Stages creation inside Pipelines
### Problem to solve
It will be nice to have this feature out of the box.
### Intended users
All users/projects.
### Further details
Use cases when it will apply to pipelines.
### Proposal
Providing more flexibility.
### Permissions and Security
UI available...
### Availability & Testing
* Unit test changes
* Integration test changes
* E2E
### What does success look like, and how can we measure that?
It will provide more flexibility and possibilities when creating pipelines.
### What is the type of buyer?
All users.
### Is this a cross-stage feature?
Yes.
### Links / references
....
issue