Add StoreAwaitedActionDb API

This is pre-work for the introducing a distributed redis scheduler. This
is the API for how to interact between the scheduler and the stores.

towards: #359

nativelink-scheduler/BUILD.bazel

@@ -19,6 +19,7 @@ rust_library(
         "src/memory_awaited_action_db.rs",
         "src/platform_property_manager.rs",
         "src/property_modifier_scheduler.rs",
+        "src/store_awaited_action_db.rs",
         "src/simple_scheduler.rs",
         "src/simple_scheduler_state_manager.rs",
         "src/worker.rs",

nativelink-scheduler/src/awaited_action_db/awaited_action.rs

@@ -112,6 +112,10 @@ impl AwaitedAction {
         self.version.0
     }
 
+    pub(crate) fn set_version(&mut self, version: u64) {
+        self.version = AwaitedActionVersion(version);
+    }
+
     pub(crate) fn increment_version(&mut self) {
         self.version = AwaitedActionVersion(self.version.0 + 1);
     }

nativelink-scheduler/src/lib.rs

@@ -22,5 +22,6 @@ pub mod platform_property_manager;
 pub mod property_modifier_scheduler;
 pub mod simple_scheduler;
 mod simple_scheduler_state_manager;
+pub mod store_awaited_action_db;
 pub mod worker;
 pub mod worker_scheduler;