Remove LedgerSeeder class from agent

[pimotte]

The LedgerSeeder is code that we execute on startup, but is not needed in normal deployment.

There is a branch with a seeder-cli tool: https://github.com/Quintor/StudyBits/tree/feature/seeder-cli

• [ ] Remove LedgerSeeder from agent code base
• [ ] Modify docker-compose integration test to use the CLI tool to set everything up before running the test.