Normalize user_tokens table

## Normalize user_tokens table

### Acceptance Criteria
1. ~~New table `user_token_types` exists which holds all valid user token types.~~ Implement on https://github.com/synapsestudios/api-template/issues/53.
1. ~~Token types are included in the DB install files.~~ Implement on https://github.com/synapsestudios/api-template/issues/53.
1. Entity still assumed to have a string field, and mapper simply joins to return the correct data.
1. Correct ID is set on creation of tokens.

### Tasks
- None

### Additional Notes
- None