Convert Databind to a library

[MysteryBlokHed]

Closes #129

Adds a lib.rs file with public modules and uses and updates the Cargo.toml to point to main.rs for a binary. This allows other people to use functions from the Databind library while still having the CLI without creating a new package, and also allows for testing of individual functions in the future.

• [x] Change pub to pub(crate) for functions only useful for this specific CLI
• [x] Move code potentially useful to other devs from main.rs to public functions in a different file
• [x] Add documentation where needed
  • [x] Document modules
  • [x] Document structs
  • [x] Document enums
  • [x] Document properties/values of structs/enums

[MysteryBlokHed]

I think that should be everything useful done. I'm not sure whether I should move the main loop from main.rs to a public function or not, but that can be done in the future if it seems like a good idea.