Introduce cdk-database

[crodas]

Description

This is a crate that makes it easier to create a database instance based on an enum that can be constructed from a CLI or an env variable.

This PR has been abstracted from #509, which makit es easier to create binaries that share the same settings / databases as the mintd web-server.

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Notes to the reviewers

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Suggested CHANGELOG Updates

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Checklist

• I followed the code style guidelines
• I ran just final-check before committing

[thesimplekid]

I don't think this adds much benefit but it does add more overhead for us with an extra crate. Projects that use cdk as a lib will only want one database so they can just import the crate for the one they want to use (sqlite/redb). Where something like mintd where we want to support both can just import both and do his internally.

[crodas]

Makes sense, I'll undo this in #509