FTS completion

For SRCNet0.1 a Rucio instance needs to use the SKA IAM. This can be achieved if we deploy our own FTS instance configured to use SKA IAM, and if we then move RSEs to use SKA IAM. Alternatively, we switch to SKA IAM but continue to use the CERN pilot FTS instance.
Work has been continuing for some time to deploy our own FTS instance, and this is an important service to build expertise in within the ART.

First - create a backup plan. What would be the minimal FTS solution to achieve readiness for v0.1 testing. 
Second - a decision is made with Rob B approval, whether to pursue the backup solution or full solution now.

If the backup plan:

• we need acceptance criteria / this feature to define what is to be completed in PI23

If the full solution, these are the original ACs:

• FTS migrated to new OS (details follow)
• Token refactor FTS release implemented and tested
• Plan for SRCNet0.1: use of own FTS or CERN Pilot FTS
• Proven transfers using SKA IAM tokens between at least two storage elements