Add default fields relations information

[wellingguzman]

All fields and collections needs directus_fields, directus_collections and directus_relations information in order to work properly.

[benhaynes]

• Collections require a value within directus_collections to be "managed".
• Fields should always show up (even without a directus_fields record), unless they are blacklisted in permissions.
• Fields not in directus_fields should pull the basic info from the DB schema and returned in API responses. They should also have a managed flag set to true if they have a record.

[wellingguzman]

This will be another "big" ticket that needs to be separated from this.

What actually I wanted to do from this ticket is set the default interface and data types for all the directus fields and relations.

[wellingguzman]

Moved your notes to a new ticket (#60)

[wellingguzman]

I actually wanted to add the relations information, I changed the ticket title accordingly.