Introduce stacked filtering (#6273)

* Introduce stacked filtering.

* Benchmarks

* Remove unneeded crates

* Fix proxy type's permissiveness checks.

* Repot multisig to make utility stateless.

* Repot filter stack impl into macro

* Fix wasm build

* Tests

* Final test.

* Tests for the macro

* Fix test

* Line width

* Fix

* Update frame/multisig/src/benchmarking.rs

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

* Update primitives/std/with_std.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Grumble

* Update frame/support/src/traits.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update frame/support/src/traits.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update frame/support/src/traits.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update frame/support/src/traits.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update frame/support/src/traits.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update frame/multisig/src/tests.rs

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

* Update frame/multisig/src/tests.rs

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

* Grumble

* Migration

* Grumble

* Comments

* Migration

* Fix

* Fix

* Line width

* Allow unused

* Update frame/multisig/src/lib.rs

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* Fix up grumble.

* Remove Utility constraint in NonTransfer

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

substrate/Cargo.toml

@@ -84,6 +84,7 @@ members = [
 	"frame/indices",
 	"frame/membership",
 	"frame/metadata",
+	"frame/multisig",
 	"frame/nicks",
 	"frame/offences",
 	"frame/proxy",