Next phase evolution of contract-based retirement operations

### Problem description
Current implementation of retirement operations requires manual actions - for example to update the status of smart contracts, to receive requests for creating 'pools' etc. This is because Hedera smart contracts are external to Guardian, and can be updated directly (not through Guardian) via Hedera API. However the need for manual actions imposes certain requirements on the user - to remember to do it, etc which would be best to avoid.

### Requirements
Introduce an automatic updating of Guardian 'cache' view of the smart contracts configuration status such that:

- as much as possible it is a free operation (does not require user to pay hbar) - probably based on parsing events
- the API for notifications is defined such that any 3rd party implementing their own smart contracts can integrate with Guardian out-of-the box by implementing their notifications to be compliant with this specification
- represents the full state required for Retirement operation through Guaridan - includes both the configuration of the contracts and various other settings such as requests for approval etc

### Definition of done

- Functionality is implemented as per above
- Reference documentation is created explaining the features, defining the API, and a user guide

### Acceptance criteria
The state of Guardian when it comes to token retirement is always 'current' - reflecting the actual state of the corresponding Hedera smart contracts