Make cloud.instance_info.status an enum

[owenniles]

See #4972

[philippemnoel]

@owenniles @MauAraujo is this still relevant even though we're removing most of the webserver?

[MauAraujo]

I will close this issue since we will no longer use enums on the new database schema. While having a lot of benefits, enums are still somewhat unsupported on the libraries we use for interacting with the database. In order for them to work, we need to do some workarounds.

For example, the Hasura client only supports enums if they are declared in the public schema, and in order for them to work we need to create go types with the exact same name, which results in unidiomatic code. The db driver also has trouble when encoding/decoding custom types, as can be seen here.