Validate 2000 general election candidate and contests
Validate 2000 general election candidate and contests

Factor code into helper functions for validating candidates and
contests for a given election.

Addresses https://github.com/openelections/core/issues/36

datamade/openelections-core,datamade/openelections-core,openelections/openelections-core,cathydeng/openelections-core,openelections/openelections-core,cathydeng/openelections-core