feat(core): implement message model

closes #273

crates/core/models/src/v0/mod.rs

@@ -3,8 +3,10 @@ mod channel_invites;
 mod channel_unreads;
 mod channel_webhooks;
 mod channels;
+mod embeds;
 mod emojis;
 mod files;
+mod messages;
 mod server_bans;
 mod server_members;
 mod servers;
@@ -16,8 +18,10 @@ pub use channel_invites::*;
 pub use channel_unreads::*;
 pub use channel_webhooks::*;
 pub use channels::*;
+pub use embeds::*;
 pub use emojis::*;
 pub use files::*;
+pub use messages::*;
 pub use server_bans::*;
 pub use server_members::*;
 pub use servers::*;