Provide interface for query Execution

[els0r]

As a precursor to #43, this issue aims to provide a more generic approach to obtaining query results. With #43, there will be two ways of getting them:

• via accessing goDB data and aggregating it
• via consolidated data from a query run on goDB

The latter being important when aggregating results across several hosts.

Proposal is an interface, which goDB and any other tools that call goQuery implement:

type Runner interface {
    Run(ctx context.Context, stmt *query.Statement) (result results.Result, err error)
}

Implications of this are a major restructuring (not necessarily a refactor) of the package structure inside pkg (mainly query and goDB) and having a goDBQueryRunner execute queries.

Note on naming: going for Runner vs. Executor because the latter just sounds off.