Decouple Stkaing and Election - Part1: Support traits (#7908)

* Base features and traits.

* Fix the build

* Remove unused boxing

* Self review cleanup

* Fix build

substrate/Cargo.lock

@@ -8357,6 +8357,17 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "sp-election-providers"
+version = "2.0.0"
+dependencies = [
+ "parity-scale-codec",
+ "sp-arithmetic",
+ "sp-npos-elections",
+ "sp-runtime",
+ "sp-std",
+]
+
 [[package]]
 name = "sp-externalities"
 version = "0.8.1"
@@ -8453,6 +8464,7 @@ dependencies = [
  "rand 0.7.3",
  "serde",
  "sp-arithmetic",
+ "sp-core",
  "sp-npos-elections-compact",
  "sp-runtime",
  "sp-std",