Document the strategy for veda-auth-central vs airavata-custos

[j08lue]

As far as I understand, pretty much all the code in veda-auth-central is a copy of airavata-custos and all features planned to be used on VEDA are going to be implemented upstream and only configured for use on VEDA.

Upstream integration also includes a web UI for configuring auth, part of which has already been designed and which will replace airavata-custos-portal.

This strategy should be documented somewhere, probably in the README, where we already have some notes on choice of technologies and architecture.

Can we also record somewhere (this ticket is fine), how many other projects are relying on Custos and will share the implementation and maintenance of any newly implemented features? This would help estimate the longer-term maintenance burden on VEDA.

Acceptance criteria

• Documented the strategy for veda-auth-central <> airavata-custos relationship