Revise API Request/Response Objects

[maakinoh]

For EF29 or the future, it may be nice to revise the HTTP API to use DTOs instead of the real database records.

Currently, we have some controllers which are using the raw records like DealersController:

public async Task<ActionResult> PostDealerAsync([EnsureNotNull][FromBody] DealerRecord record)

And some who don't like FursuitController:

public async Task<ActionResult> PostFursuitBadgeRegistrationAsync([FromBody] FursuitBadgeRegistration registration)

Working with the raw DB records can cause some problems like ID collisions and exposing sensitive or unneeded information.

I suggest could we implement a uniform DTO system for each request/response/database record.

This also relates to #131