Improve devops adoption seed

What does this MR do and why?

Improve devops adoption seed

• Allow to run seed for same group multiple times, there was a bug where EnabledNamespaces could cause foreign key uniqueness violation.
• Accept GROUP_ID to run seed for an existing group
• Output group URL at the end of the seed

related to #413257 (closed)

How to set up and validate locally

1. Run for a couple of random groups FILTER=devops_adoption bundle exec rake db:seed_fu
2. Run for a specific group FILTER=devops_adoption DEVOPS_GROUP_ID=9 bundle exec rake db:seed_fu

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.