Custom runtime module errors (#3433)

* srml-system checks

* wip

* more modules compiles

* node-runtime checks

* build.sh passes

* include dispatch error in failed event

* revert some unnecessary changes

* refactor based on comments

* more compile error fixes

* avoid unnecessary into

* reorder code

* fixes some tests

* manually implement encode & decode to avoid i8 workaround

* more test fixes

* more fixes

* more error fixes

* Apply suggestions from code review

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* address comments

* test for DispatchError encoding

* tyep alias for democracy

* make error printable

* line width

* fix balances tests

* fix executive test

* fix system tests

* bump version

* ensure consistent method signature

* Apply suggestions from code review

Co-Authored-By: Gavin Wood <github@gavwood.com>

* changes based on review

* Add issue number for TODOs

* fix

* line width

* fix test

* Update core/sr-primitives/src/lib.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Update core/sr-primitives/src/traits.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Update srml/council/src/motions.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Update srml/council/src/motions.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* update based on review

* More concrete macro matching

* fix test build issue

* Update hex-literal dependency version. (#3141)

* Update hex-literal dep version.

* Update lock file.

* Start to rework the new error handling

* More work to get it back compiling

* Start to fix after master merge

* The great transaction error handling refactoring

* Make `decl_error` errors convertible to `&'static str`

* Make srml-executive build again

* Fix `sr-primitives` tests

* More fixes

* Last round of fix ups

* Fix build

* Fix build

* Apply suggestions from code review

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Rename some stuff

* Fixes after master merge

* Adds `CheckBlockGasLimit` signed extension

* Remove debug stuff

* Fix srml-balances test

* Rename `InvalidIndex` to `CannotLookup`

* Remove weird generic parameters

* Rename function again

* Fix import

* Document the signed extension

* Change from `Into` to `From`

* Update srml/contracts/src/lib.rs

Co-Authored-By: Sergei Pepyakin <sergei@parity.io>

* Fix compilation

* Update srml/contracts/src/lib.rs

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Update core/sr-primitives/src/transaction_validity.rs

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Remove unused code

* Fix compilation

* Some cleanups

* Fix compile errors

* Make `TransactionValidity` a `Result`

* Apply suggestions from code review

Co-Authored-By: Gavin Wood <gavin@parity.io>

* Beautify the code a little bit and fix test

* Make `CannotLookup` an inherent error declared by `decl_error!`

* Adds some documentation

* Make `ApplyOutcome` a result

* Up the spec_version

* Apply suggestions from code review

Co-Authored-By: Gavin Wood <gavin@parity.io>
Co-Authored-By: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com>

substrate/core/rpc/api/src/author/error.rs

@@ -101,15 +101,15 @@ impl From<Error> for rpc::Error {
 				message: format!("Verification Error: {}", e).into(),
 				data: Some(format!("{:?}", e).into()),
 			},
-			Error::Pool(PoolError::InvalidTransaction(code)) => rpc::Error {
+			Error::Pool(PoolError::InvalidTransaction(e)) => rpc::Error {
 				code: rpc::ErrorCode::ServerError(POOL_INVALID_TX),
 				message: "Invalid Transaction".into(),
-				data: Some(code.into()),
+				data: serde_json::to_value(e).ok(),
 			},
-			Error::Pool(PoolError::UnknownTransactionValidity(code)) => rpc::Error {
+			Error::Pool(PoolError::UnknownTransaction(e)) => rpc::Error {
 				code: rpc::ErrorCode::ServerError(POOL_UNKNOWN_VALIDITY),
 				message: "Unknown Transaction Validity".into(),
-				data: Some(code.into()),
+				data: serde_json::to_value(e).ok(),
 			},
 			Error::Pool(PoolError::TemporarilyBanned) => rpc::Error {
 				code: rpc::ErrorCode::ServerError(POOL_TEMPORARILY_BANNED),
@@ -133,7 +133,7 @@ impl From<Error> for rpc::Error {
 			},
 			Error::Pool(PoolError::ImmediatelyDropped) => rpc::Error {
 				code: rpc::ErrorCode::ServerError(POOL_IMMEDIATELY_DROPPED),
-				message: "Immediately Dropped" .into(),
+				message: "Immediately Dropped".into(),
 				data: Some("The transaction couldn't enter the pool because of the limit".into()),
 			},
 			Error::UnsupportedKeyType => rpc::Error {