RBAC registration - record key rotation in role data

[bkioshn]

Summary

Record key rotation in role data

Description

Record key rotation in role data.
Key rotation here is the number of published key for each key in role in the RBAC registration.

Example

• Making first valid CIP509 reg role 3 with signing key 0x123 -> should be rotation 0
• Making another valid CIP509 reg role 3 with signing key 0x456 -> should be rotation 1
• Making invalid CIP509 reg role 3 with signing key 0x678 -> no rotation because invalid
• Making another CIP509 reg role 3 with signing key 0xabc -> should be rotation 2
• Making another CIP509 reg role 3 with signing key 0x123 -> this should not be add new rotation because it is redundant to rotation 0

We need to be able to get the nth key from the chain for a role.