refactor(sql): recreate keypairs table

Removed unused `addr` and `created` field.
`is_default` boolean flag is moved into `config` row
pointing to the current default key.

src/context.rs

@@ -1318,6 +1318,7 @@ mod tests {
             "socks5_port",
             "socks5_user",
             "socks5_password",
+            "key_id",
         ];
         let t = TestContext::new().await;
         let info = t.get_info().await.unwrap();