- limit missing headers results set to 100 so that extraction doesn't
excessively block delegation
- wrap checked headers functions in repository struct
- move storage repository to factory, to correspond with event
repository path
- remove unused files
- reformat sql
- remove line breaks in imports
towards generic method polling and reposito;y; config settings to
filterevents/methods by account address; refactoring some stuff out of
repo and into converter; remove fetcher and instead call
blockchain's FetchContractData directly; finishing tests
