ARI: merge OSB API area into CAPI

[stephanme]

• OSB API area got orphaned when the last approver was removed by Inactive users to be removed from ARI WG #1162 (inactive user cleanup)
• decision in ARI WG meeting on 25-05-27 to add the repos to the CAPI area

[stephanme]

In the end, this is just documentation as the repos are not located in cloudfoundry github org. Once merged, the access rights in github org openservicebrokerapi should be consolidated.

We should consider moving the repos into the cloudfoundry org to benefit from the org automation. rfc-0036-multiple-github-orgs.md requires that a WG contains only repos from one CFF github org.
On the other hand, https://www.openservicebrokerapi.org/ aims to define a platform independent service integration which may justify an own github org.