Added solana sdk and executor

src/executor/mod.rs

@@ -0,0 +1,7 @@
+use solana_sdk::pubkey::Pubkey;
+
+#[allow(async_fn_in_trait)]
+pub trait Executor {
+    async fn buy(&self, token: Pubkey, amount: f64) -> anyhow::Result<()>;
+    async fn sell(&self, token: Pubkey, amount: f64) -> anyhow::Result<()>;
+}