Organization needs to have a few first class attributes and tags

**Organization kyc attributes are missing:**

Organization object does not have :
* date_of_incorporation
* tags (To store registration and tax_ids needed for peer2peer kyc).

**Preferred solution**
Add first class attributes :
1. date_of_incorporation ,
2. an array of credentials ( to hold registration id , tax_id etc)
3. tags to allow for extensibility.

** Alternate solution **
Just add tags and let network facilitator dictate the tag groups. ( though this is workable, I think creds and date of incorporation must be first class attributes on organization entity)

**Additional context**
This would be useful in [beckn.json feature](https://github.com/beckn/beckn-utilities/issues/43) also. @ravi-prakash-v

Review the Organization entity definition in the protocol specification, then read the linked beckn.json feature issue for context. Resolve whether credentials, date_of_incorporation, and tags should be first-class fields or whether tags alone are sufficient; done means the chosen Organization schema is specified consistently.

Written by the indexing model from the issue text.