Filter invalid Singer Messages in the worker

[cgardens]

What

• As a compromise in this PR Add postgres tap bugfixes & integration tests #229 @sherifnada turned on allowing additionalProperties in the singer models in the singer protocol. Due to some idiosyncrasies in Json2Pojo, it means effective nothing gets validated by its parser anymore. We want to retain validation that the fields we care about still look right.

How

• This PR reused the validator that we use in the API to run these validations.
• It wraps it in a predicate for testing purposes that is used in the tap stream.

Gotcha

• There's a really awful hack having to do with java resources see inline comment for more details.

[cgardens]

Hack: The problem here is that if this path is just json when we execute code in dataline-workers, the invocation of prepareSchemas that runs in SingerConfigSchema, only finds the resources from dataline-config:models, NOT dataline-singer. It seems like because they store their configs in the same relative path in their resources, one clobbers the other.

This seems to be an idiosyncrasy with resources that I don't fully understand. This unblocks us for now. I am going to read more carefully about java resources and hopefully come up with a less spooky solution. In the meanwhile, it seems like we need our config style packages to not store their json configs in paths with the same names.