Pallet-Multisig to framev2 (#8741)

* the great migration

* benchmarks to work

* unnecessary T: Config

* Update frame/multisig/src/lib.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

* Update frame/multisig/src/lib.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

* Update frame/multisig/src/lib.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

* Update frame/multisig/src/lib.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

* Update frame/multisig/src/lib.rs

* line width

* get to compile

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>
Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>