Fix bug with import and cleanup

[austinabell]

Summary of changes
Changes introduced in this pull request:

• Fixes bug where if starting on a fresh data directory, importing a chain would fail during validations because the genesis was not initialized
• Cleaned up code and setup import to be used outside of forest (I'm benchmarking and testing using an external bin to avoid compiling all of forest, only what I need)
• Removed DatabaseService trait, very useless, no need to ever swap out database implementation at runtime, should be a build flag

Reference issue to close (if applicable)

Closes

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