Adds error handling to validator client service

validator_client/src/error.rs

@@ -0,0 +1,22 @@
+use slot_clock;
+
+use error_chain::{
+    error_chain, error_chain_processing, impl_error_chain_kind, impl_error_chain_processed,
+    impl_extract_backtrace,
+};
+
+error_chain! {
+   links  { }
+
+   errors {
+    SlotClockError(e: slot_clock::SystemTimeSlotClockError) {
+        description("Error reading system time"),
+        display("SlotClockError: '{:?}'", e)
+    }
+
+    SystemTimeError(t: String ) {
+        description("Error reading system time"),
+        display("SystemTimeError: '{}'", t)
+    }
+   }
+}