BoundedVec + Shims for Append/DecodeLength (#8556)

* prototype for shawn

* Clean and document it

* Add more docs

* Move imports

* Some changes for easier compat.

* revert exmaple pallet

* rename

* BoundedVec for AccountLocks (#8580)

* Example with balances

* Fix tests

* Make it indexable

* fix

* Fix tests

* fix test

* Fix collective as well

* Fix test

* Update frame/support/src/storage/mod.rs

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

* Repot and add for value

* Add for map and double map

* Final touches.

* Update frame/support/src/storage/bounded_vec.rs

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

* Add a few more tests

* Add import

Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>