add: custom like emoji per instance, fix like

This fixes the fact that likes on mastodon didn't get federated properly and let's instance admins choose a custom emoji

packages/backend/src/models/Meta.ts

@@ -533,4 +533,10 @@ export class MiMeta {
 		default: 0,
 	})
 	public notesPerOneAd: number;
+
+	@Column('varchar', {
+		length: 500,
+		nullable: true,
+	})
+	public defaultLike: string | null;
 }