interface: Re-add stake files from sdk with history

interface/src/config.rs

@@ -0,0 +1,33 @@
+//! config for staking
+//!  carries variables that the stake program cares about
+
+#[deprecated(
+    since = "1.16.7",
+    note = "Please use `solana_sdk::stake::state::{DEFAULT_SLASH_PENALTY, DEFAULT_WARMUP_COOLDOWN_RATE}` instead"
+)]
+pub use super::state::{DEFAULT_SLASH_PENALTY, DEFAULT_WARMUP_COOLDOWN_RATE};
+use serde_derive::{Deserialize, Serialize};
+
+// stake config ID
+crate::declare_deprecated_id!("StakeConfig11111111111111111111111111111111");
+
+#[deprecated(
+    since = "1.16.7",
+    note = "Please use `solana_sdk::stake::state::warmup_cooldown_rate()` instead"
+)]
+#[derive(Serialize, Deserialize, Debug, PartialEq, Clone, Copy)]
+pub struct Config {
+    /// how much stake we can activate/deactivate per-epoch as a fraction of currently effective stake
+    pub warmup_cooldown_rate: f64,
+    /// percentage of stake lost when slash, expressed as a portion of u8::MAX
+    pub slash_penalty: u8,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            warmup_cooldown_rate: DEFAULT_WARMUP_COOLDOWN_RATE,
+            slash_penalty: DEFAULT_SLASH_PENALTY,
+        }
+    }
+}