Add snapshotter extension

[trinitys7]

Description

This PR is to add the snapshotter extension to sync wasm directory :

• Move default wasm directory from runtime dictionary into chain home folder, ibc_08-wasm_client_data will be subfolder of ~/.simapp
• Add IteratorCode function to iterate wasmcode that saved in chain state.
• Testing: setup testing app with snapshot extension enable.

closes: #4275

---

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[trinitys7]

hi @damiannolan, now this PR allows edit from maintainers.

[alpe]

This code looks familiar ;-)

[DimitrisJim]

full review pending on merge of #4292

[colin-axner]

Reviewed everything except the iterate code. Thanks @trinitys7 for getting this work started and @DimitrisJim for pushing it along 🙏

[colin-axner]

duplicate contract test case? Or are we assuming a node would never be provided such a snapshot?

[damiannolan]

duplicate contract test would fail with the current test structure on the initial store code call in 08-wasm here: https://github.com/cosmos/ibc-go/blob/feat/wasm-clients/modules/light-clients/08-wasm/keeper/keeper.go#L103-L105

We might be able to work around it tho.

But that being said, all calls to the vm StoreCode are idempotent so it should just behave as if its a no-op if its ever reached. I think it would be quite hard for a node to obtain a snapshot with duplicate contracts, impossible even?

[damiannolan]

Hey @trinitys7, apologies that this PR has been waiting in the wings so long! Finally we can pick up the remaining work on this. I will resolve the conflicts and can contribute some commits to pushing this forward. Thank you for getting this started ❤️

[colin-axner]

Amazing work! Everything looks great to me, only comment would be to add an assertion that the dest wasm app has no contracts before the snapshots are restored

[damiannolan]

Dropping my approval on this now, I think its looking pretty good. I'd like to try to improve the tests in future but I think this is good to move forward with for now.

Thank you for collaboration on this PR @trinitys7 @DimitrisJim, and @colin-axner for reviews ❤️ ❤️ ❤️