Remove support for group calls and guild sync

Calls and guild sync are essentially leftovers from selfbot support
removal, the former moreso.

Removes the following `model::event` structs:

- CallCreateEvent
- CallDeleteEvent
- CallUpdateEvent
- GuildSyncEvent

which also removes the following `model::event::Event` variants:

`client::gateway::Shard::sync_calls` has been removed.

The following `client::Client` methods have been removed:

- `on_call_create`
- `on_call_delete`
- `on_call_update`
- `on_guild_sync`

Removes the following items on `ext::cache::Cache`:

```
ext::cache::Cache::{
    // fields
    calls,
    // methods
    get_call,
    update_with_call_create,
    update_with_call_delete,
    update_with_call_update,
    update_with_guild_sync,
}
```

Voice structs and methods now take solely a `guild_id` instead of a
`target`, due to the handling of 1-on-1 and group calls being removed.

This continues off commit d9118c0.<Paste>

0 files changed, 0 insertions, 0 deletions