Audit fixes for election/staking decoupling part 2 (#8167)

* Base features and traits.

* pallet and unsigned phase

* Undo bad formattings.

* some formatting cleanup.

* Small self-cleanup.

* Make it all build

* self-review

* Some doc tests.

* Some changes from other PR

* Fix session test

* Update Cargo.lock

* Update frame/election-provider-multi-phase/src/lib.rs

Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>

* Some review comments

* Rename + make encode/decode

* Do an assert as well, just in case.

* Fix build

* Update frame/election-provider-multi-phase/src/unsigned.rs

Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>

* Las comment

* fix staking fuzzer.

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_election_provider_multi_phase --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/election-provider-multi-phase/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* Add one last layer of feasibility check as well.

* Last fixes to benchmarks

* Some more docs.

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_election_provider_multi_phase --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/election-provider-multi-phase/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_election_provider_multi_phase --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/election-provider-multi-phase/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* Some nits

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_staking --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/staking/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* Fix doc

* Mkae ci green

* Audit fixes for election-provider: part 2 signed phase.

* Fix weight

* Some grumbles.

* Try and weigh to get_npos_voters

* Fix build

* Fix line width

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_staking --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/staking/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* Fix tests.

* Fix build

* Reorg some stuff

* More reorg.

* Reorg done.

* Fix build

* Another rename

* Fix build

* Update frame/election-provider-multi-phase/src/mock.rs

Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>

* nit

* better doc

* Line width

* Fix build

* Self-review

* Self-review

* Fix wan

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_election_provider_multi_phase --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/election-provider-multi-phase/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_staking --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/staking/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* fix build and review comments.

* Update frame/election-provider-multi-phase/src/lib.rs

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

* add comment

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>
Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>
Co-authored-by: Parity Benchmarking Bot <admin@parity.io>
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>

substrate/frame/system/src/offchain.rs

@@ -38,10 +38,10 @@
 //!
 //! To be able to use signing, the following trait should be implemented:
 //!
-//! - [`AppCrypto`](./trait.AppCrypto.html): where an application-specific key
-//!   is defined and can be used by this module's helpers for signing.
-//! - [`CreateSignedTransaction`](./trait.CreateSignedTransaction.html): where
-//!   the manner in which the transaction is constructed is defined.
+//! - [`AppCrypto`](./trait.AppCrypto.html): where an application-specific key is defined and can be
+//!   used by this module's helpers for signing.
+//! - [`CreateSignedTransaction`](./trait.CreateSignedTransaction.html): where the manner in which
+//!   the transaction is constructed is defined.
 //!
 //! #### Submit an unsigned transaction with a signed payload
 //!
@@ -53,7 +53,6 @@
 //! #### Submit a signed transaction
 //!
 //! [`Signer`](./struct.Signer.html) can be used to sign/verify payloads
-//!
 
 #![warn(missing_docs)]
 
@@ -473,7 +472,7 @@ pub trait SendTransactionTypes<LocalCall> {
 	/// The runtime's call type.
 	///
 	/// This has additional bound to be able to be created from pallet-local `Call` types.
-	type OverarchingCall: From<LocalCall>;
+	type OverarchingCall: From<LocalCall> + codec::Encode;
 }
 
 /// Create signed transaction.