Update 08-wasm documentation and migration docs for v0.3.x

[crodriguezvega]

Documentation for 08-wasm and migration docs for v0.3.x with ibc-go v9.0 should be updated/added with changes from #6088, #6164, #6176, #6177.

[DimitrisJim]

Some notes:

• Many of the types in ibcwasm don't need to be mentioned, they were already private.
• Types moved to internal/store were previously private in types.

Additions:

• Wasm(*) functions on the keeper (contract_keeper.go), these were previously private in types/. Using them in light_client_module necessitated they be made public.
• types.CostJSONDeserialization has been made public. (we could possibly move this in keeper?)
• MaxWasmSize has been added (removing MaxWasmByteSize function that simply returned it)

Modifications:

• Keeper struct has new GetVM, GetChecksums, Logger methods.
• InitializePinnedCodes was made a keeper method from a standalone function.
• Accessing state has moved from types/ to keeper/. Keeper object now has HasChecksums and GetAllChecksums methods
• querier.go has been moved to keeper/ pkg from types/. NewDefaultQueryPlugins and QueryPlugins are moved there.
• AcceptListStargateQuerier has an additional argument for the queryRouter.
• Signature of WithQueryPlugins has changed, argument is now QueryPlugins struct in keeper/.
• VMGasRegister has moved from the types/ package to the keeper/ package.

Removals:

• All the client state methods that were moved to light client module interface.
• Logger standalone function in types/ (has been moved on Keeper).
• MaxWasmByteSize has been removed.

Doc changes noticed (reading https://ibc.cosmos.network/main/ibc/light-clients/wasm/overview):

• Documentation on Integration needs updating to modify call to initialize pinned codes (now defined on keeper) in the given example for app.go.