[WIP][Persistence][Core][Savepoints/Rollbacks] Implement KISS SavePoints - Serialize WorldState from Persistence - JSON POC - (Issue #327)

[deblasis]

Description

⚒️ work in progress - proof of concept ⚒️

This PR is meant to provide an example of how the implementation that relies on a serialized state that uses JSON would look like.

The implementation is not complete.

The test:

(source: persistence/test/savepoints_test.go)

and related code provide an example of how it would look like.

The steps are:

• Given a PostgresContext, we can create a SavepointFactory
• The SavepointFactory can create Savepoints
• A Savepoint implements PersistenceReadContext and therefore it provides access to the state like if it was the database (this is to allow ephemeral state)
• The test shows two examples of queries performed on this serialized state (GetAllAccounts and GetAccountAmount)

Issue

If we choose to complete the implementation, it would fix #327

Type of change

Please mark the relevant option(s):

• New feature, functionality or library
• Bug fix
• Code health or cleanup
• Major breaking change
• Documentation
• Other

List of changes

Testing

• make develop_test; if any code changes were made
• Docker Compose LocalNet; if any major functionality was changed or introduced
• k8s LocalNet; if any infrastructure or configuration changes were made

Required Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added, or updated, godoc format comments on touched members (see: tip.golang.org/doc/comment)
• I have tested my changes using the available tooling
• I have updated the corresponding CHANGELOG

If Applicable Checklist

• I have updated the corresponding README(s); local and/or global
• I have added tests that prove my fix is effective or that my feature works
• I have added, or updated, mermaid.js diagrams in the corresponding README(s)
• I have added, or updated, documentation and mermaid.js diagrams in shared/docs/* if I updated shared/*README(s)

[github-actions]

The changelog validation failed with the following output:

Missing changelog in module: consensus/

Missing changelog in module: persistence/

Missing changelog in module: shared/

Changelog verification failed. See error messages for more detail.

Please update the relevant CHANGELOG.md files and ensure they follow the correct format.

[github-actions]

The changelog validation failed with the following output:

Missing changelog in module: persistence/

Missing changelog in module: shared/

Changelog verification failed. See error messages for more detail.

Please update the relevant CHANGELOG.md files and ensure they follow the correct format.

[Olshansk]

Closing out the draft PR as it'll be used as a reference and reopened if/when we fully implement it.