Feature/core 242 entrypointcalled journal entry

[zajko]

CORE-242: EntryPointCalled and Ret execution journal entries

Adds two new transform kinds to the execution journal that record contract call/return at runtime.

• TransformKindV2::EntryPointCalled execute result whenever wasm session code or a contract attempts to do an entry point call. This also applies to VM2 constructor and upgrade method calls.
• TransformKindV2::EntryPointCalled is not stored to global state
• if an entry point call is successful there will be a TransformKindV2::Ret(RetValue::Unit) execution journal entry if the contract didn't call the return functionality on it's own.
• if a contract (or session code) called the return functionality and passed no output, there will be a TransformKindV2::Ret(RetValue::Unit) execution journal entry
• When calling session code the TransformV2 entry will look like:

TransformV2 {
  key: <initiator_key>
  kind: TransformKindV2::EntryPointCalled(None, "call")
}

• When session code calls a stored contract the TransformV2 entry will look like:

TransformV2 {
  key: <initiator_key>
  kind: TransformKindV2::EntryPointCalled(Some(<hash_addr_of_called_contract>, <called_method>)
}

• When stored contract calls a stored contract the TransformV2 entry will look like:

TransformV2 {
  key: <key_of_contract>
  kind: TransformKindV2::EntryPointCalled(Some(<hash_addr_of_nested_called_contract>, <nested_called_method>)
}

• The TransformV2 entry produced will be keyed differently - it always uses the callee key denoting that it's the callee returning the "program counter" to whatever was calling it.