Policies povs

DG reorganised the HIFIS AAI docs. (Thanks! 🙏)

Even though some files were deleted, all the information is still there, just shuffled around. For example, "how to register a service" and "how to implement a service" were merged under "Guidelines for services".

In addition, policy info were filled where it was missing.

Under this new structure, it becomes more clear what is still missing:

• how to integrate a service if you don't use unity (and corresponding info for users on how to gain access to these services)
• more info on entitlements (the recent discussions on AARC G002 schema)
• the "perspective" section (future AAI developments)
• possibly more "concepts"
• mailinglists section: is it up to date?
• a place to collect per service info on supported VOs, assurance, etc
• if necessary, clearer and more complete info in the "organisational" section of each guideline.