Remove tendermint-db dependency

[alpe]

Resolves #404

• Inline Tendermint's Interator interface
• Inline Tendermint's MemDB for testing

[webmaster128]

🏅

Not sure when to best merge this though. Does this change and API?

[webmaster128]

I take care of the CI fail. Not related to your work.

[DongLieu]

I have an Interator Interface problem.

Currently, Wasmvm's KVStore and Cosmos-SDK's KVStore differ in the Iterator interface.

Specifically in the main SDK branch:
Iterator(start, end []byte) (Iterator, error)
with Iterator = dbm.Iterator (dbm “github.com/cosmos/cosmos-db”)

For SDK branch using cometbft:
Iterator(start, end []byte) Iterator
with Iterator = dbm.Iterator (dbm “github.com/cometbft/cometbft-db”)

Wasmvm:
Iterator(start, end []byte) Iterator
with 'Iterator = types.Iterator' ("github.com/CosmWasm/wasmvm/types")

This leads to Interator incompatibility.