Updated doc on attestorPlugin (ClaimPluginActor) and rules for Attestation Policy

[radhay-samagra]

I would like to add another similar issue on top of this, for attestation policies, I have seen attestorEntity mentioned in the docs here to set which entity can attest the claim, but I have nowhere found the implementation details on attestorPlugin attribute which I found out here. Similar issues with property attestationProperties. Can you point me out to a updated doc mentioning all of these attributes?

[pramodkvarma]

@tejash-jl @parthlawate please help and also see if we can put together quick docs on these. Thanks.