Document Integration of a CARTA server with SRC IAM for auth provision

Document Integration of a CARTA server with SRC IAM for auth provision (possible B-L?, FO = JSC?) For scalable auth mechanism for CARTA, will need to add SRC IAM as auth provider. This moves away from user/pass type mechanism used so far in testing. AC: Documentation of how to configure an SRC IAM client to perform auth for CARTA server. Example config added to ska-carta-container repo to facilitate replication.