Add adopters file to Kuadrant repositories

[pmccarthy]

What As part of work aimed at supporting the CNCF application effort, it has been recommended that we look into adding an adopters file to each of our components repositories (or have a single source that gets linked out to from multiple repos).

Examples of adopters files include:

• https://github.com/helm/helm/blob/main/ADOPTERS.md
• https://github.com/kubevirt/kubevirt/blob/main/ADOPTERS.md

[pmccarthy]

Adopters files have been added to both Authorino and Limitador repositories

• https://github.com/Kuadrant/authorino/blob/main/ADOPTERS.md
• https://github.com/Kuadrant/limitador/blob/main/ADOPTERS.md

[pmccarthy]

https://github.com/Kuadrant/authorino/pull/452 https://github.com/Kuadrant/limitador/pull/255