[BUG] Models without primary key cause 500

**Versions Used**
Kaffy: 0.10.3
Phoenix: 1.7.10
Elixir:
```
Erlang/OTP 27 [erts-15.2] [source] [64-bit] [smp:10:10] [ds:10:10:10] [async-threads:1] [jit]

Elixir 1.18.2 (compiled with Erlang/OTP 27)
```
**What's actually happening?**

We have the following schema:

```
@primary_key false
schema "auth_identity_provider" do
field :id, :string
field :name, :string

timestamps(type: :utc_datetime)
end
```

We also have this model defined as a resource for kaffy:

```
def create_resources(_conn) do
[
user_management: [
name: "User Management",
resources: [
identity_provider: [schema: App.Models.Auth.IdentityProvider]
]
]
]
end
```

Navigating to the list page of this model, I get a 500 error:

```
[error] #PID<0.11416.0> running Phoenix.Endpoint.SyncCodeReloadPlug (connection #PID<0.11410.0>, stream id 1) terminated
Server: localhost:4000 (http)
Request: GET /app/admin_tool/user_management/identity_provider
** (exit) an exception was raised:
** (MatchError) no match of right hand side value: []
(kaffy 0.10.3) lib/kaffy/resource_admin.ex:165: Kaffy.ResourceAdmin.ordering/1
(kaffy 0.10.3) lib/kaffy/resource_query.ex:43: Kaffy.ResourceQuery.get_ordering/2
(kaffy 0.10.3) lib/kaffy/resource_query.ex:12: Kaffy.ResourceQuery.list_resource/3
(kaffy 0.10.3) lib/kaffy_web/controllers/resource_controller.ex:69: KaffyWeb.ResourceController.index/2
(kaffy 0.10.3) lib/kaffy_web/controllers/resource_controller.ex:1: KaffyWeb.ResourceController.action/2
(kaffy 0.10.3) lib/kaffy_web/controllers/resource_controller.ex:1: KaffyWeb.ResourceController.phoenix_controller_pipeline/2
(phoenix 1.7.20) lib/phoenix/router.ex:484: Phoenix.Router.__call__/5
(workera_webapps 0.1.0) lib/workera_webapps_web/endpoint.ex:1: WorkeraWebappsWeb.Endpoint.plug_builder_call/2
(workera_webapps 0.1.0) deps/plug/lib/plug/debugger.ex:155: WorkeraWebappsWeb.Endpoint."call (overridable 3)"/2
(workera_webapps 0.1.0) lib/workera_webapps_web/endpoint.ex:1: WorkeraWebappsWeb.Endpoint.call/2
(phoenix 1.7.20) lib/phoenix/endpoint/sync_code_reload_plug.ex:22: Phoenix.Endpoint.SyncCodeReloadPlug.do_call/4
(plug_cowboy 2.7.3) lib/plug/cowboy/handler.ex:11: Plug.Cowboy.Handler.init/2
(cowboy 2.12.0) /Users/sebastian/workspace/workera/workera-dev-workspace/src/workera_webapps/deps/cowboy/src/cowboy_handler.erl:37: :cowboy_handler.execute/2
(cowboy 2.12.0) /Users/sebastian/workspace/workera/workera-dev-workspace/src/workera_webapps/deps/cowboy/src/cowboy_stream_h.erl:306: :cowboy_stream_h.execute/3
(cowboy 2.12.0) /Users/sebastian/workspace/workera/workera-dev-workspace/src/workera_webapps/deps/cowboy/src/cowboy_stream_h.erl:295: :cowboy_stream_h.request_process/3
(stdlib 6.2) proc_lib.erl:329: :proc_lib.init_p_do_apply/3 -
```

This happens even if I create an Admin module and specify the `ordering/1` function.

**What should happen instead?**

Kaffy should expose a way to work with models that do not have a primary key. My immediate idea would be to have a function in the admin model that let's you define which field to use as the "primary key" in case there is none defined on the model.

**Screenshots**
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