Use proper bounded vector type for nominations (#10601)

* Use proper bounded vector type for nominations

* add docs and tweak chill_other for cleanup purposes

* Fix the build

* remove TODO

* add a bit more doc

* even more docs
gushc

* Update frame/staking/src/pallet/mod.rs

Co-authored-by: Zeke Mostov <z.mostov@gmail.com>

* Update frame/staking/src/pallet/mod.rs

Co-authored-by: Zeke Mostov <z.mostov@gmail.com>

* Fix the nasty bug

* also bound the Snapshot type

* fix doc test

* document bounded_vec

* self-review

* remove unused

* Fix build

* frame-support: repetition overload for bounded_vec

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* fix

* remove the need to allocate into unbounded voters etc etc

* Don't expect

* unbreal the build again

* handle macro a bit better

Co-authored-by: Zeke Mostov <z.mostov@gmail.com>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>