Generate storage info for pallet im_online (#9654)

* Integrating WrapperOpaque from PR #9738

* Adding storage_info to pallet im-online
Changing some `Vec` to `WeakBoundedVec`
Adding the following bounds:
* `MaxKeys
* `MaxPeerInHeartbeats`
* `MaxPeerDataEncodingSize`
to limit the size of `WeakBoundedVec`

* Fix syntax

* Need to clone keys

* Changes in formatting