use binary id class in services/topics

[chase-moskal]

why is it gross that we treat any db column starting with id_* as a binary identifier?

• it's based on the naming convention of the columns. that's just gross.
• not only do our columns have those gross names for db reasons, but all of our app's business and frontend code shares that grossness
• not cool

okay so what's the alternative?

• we need processing systems that are ready to transform/serialize/deserialize certain classes
• it should be extensible, in that we can add new such classes
• our app code should be none the wiser

why didn't we like the alternative before?

• because rewriting a thousand occurances of logic that depend on the ids being strings was horrific, so we wanted to leave all those in place

why isn't that scary now?

• i think we can only use the binary id class within services/topics, so they'll only ever export id strings to the rest of the system -- so the rest of the system doesn't need to work with the binary types

[chase-moskal]

• [x] userId
• [x] appId
• [x] privilegeId
• [x] questionId
• [x] subscriptionId

• [x] subscriptionPlanId

• [x] remove id_ conversion logic

[chase-moskal]

done 33a143d00a52bcffe2af130cd0eb44ef8eb19b39