Add endpoint to show all LBRY locked up in claims

[tzarebczan]

Add an endpoint + add info to stats page

Internal Use

Acceptance Criteria

Definition of Done

• [ ] Tested against acceptance criteria
• [ ] Tested against the assumptions of the user story
• [ ] The project builds without errors
• [ ] Unit tests are written and passing
• [ ] Tests on devices/browsers listed in the issue have passed
• [ ] QA performed & issues resolved
• [ ] Refactoring completed
• [ ] Any configuration or build changes documented
• [ ] Documentation updated
• [ ] Peer Code Review performed