Feat: Add `try_state` invariants to pallets

[wischli]

Description

So far, we have not made use of the try_state hooks which are part of the try-runtime feature. It provides checks which should ensure that the state of the pallet is consistent and correct. Usually, these checks should check all of the invariants that are expected to be held on all of the storage items of some particular pallet. This hook should not alter any storage though.

This issue should serve as an entry point and only be closed once we have try_state implemented for all pallets or decided certain pallets don't need it.

Research/based on

• Similar hooks in Polkadot SDK, e.g. https://github.com/paritytech/polkadot-sdk/blob/2d3a6932de35fc53da4e4b6bc195b1cc69550300/substrate/frame/collective/src/lib.rs#L350
• https://paritytech.github.io/try-runtime-cli/frame_support/traits/trait.TryState.html

How will this affect the code base

• Improves stability

What are foreseen obstacles or hurdles to overcome?

• Should be added to CI and triggered if a PR is either a release one or contains the migration label
• Currently, try_state is only usable on a per-pallet level. See Allow runtime-wide TryState checks paritytech/polkadot-sdk#235

[lemunozm]

Love it!

I think can be quite useful for pallet-loans, checking that i.e. the portfolio can be correctly computed after a migration