Problem: MsgExec may squeeze multiple message events into a single one

## Background

For a simple transaction with multiple messages, the event log is an array in which each element corresponds to each message's produced events. e.g. https://mainnet.crypto.org:1317/cosmos/tx/v1beta1/txs/A895EE1E05935C87FBF301BB8277E091087B88C6AFF70772D5078496ADE1D8F4

However, when it is a MsgExec with multiple messages inside, the MsgExec only has one single event log and it will "collapse" all the underlying messages' events. i.e. key-value pairs of different messages with the same `type` are "squashed" into a single `type` entry. This will break the design of some message parser in which they assume the events should only be related to the message they are parsing.

https://mainnet.crypto.org:1317/cosmos/tx/v1beta1/txs/99A8D602F8025DA75310DC274A807F03C22E6CB4A12DA5270FE8B99B95A3AC30

## Task Details

### Stage 1

- Disable `MsgExec` parser as a temp measure

### Stage 2

- Enable `MsgExec` parser only if the messages inside consists of "simple message"
- Simple message means message which does not relies on event value

### Stage 3

- Evaluate case-by-case to message parser which relies on event value