Emit balance change events from the protocol

[sug0]

Describe your changes

Closes #84

Emits balance change events for the following protocol actions:

• Fee payments to validators
• PGF payments (including over IBC)
• Governance refunds
• IBC token minting/burning
• Proof-of-stake validator slashing
• WASM transfers

Indicate on which release or other PRs this topic is based on

#3102

Diff for review: https://github.com/anoma/namada/compare/tiago/move-events-to-submodules..tiago/balance-change-events (https://github.com/anoma/namada/pull/3141/files/68420a57f251ca8e68ae6960a4a0081e57c16403..406f715b416b069b310410fec20f0ba0cb7c4a06)

Checklist before merging to draft

• [x] I have added a changelog
• [x] Git history is in acceptable state

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 63.73057% with 770 lines in your changes are missing coverage. Please review.

Project coverage is 59.65%. Comparing base (ea843f7) to head (50dc3c7). Report is 21 commits behind head on main.

Files	Patch %	Lines
crates/ibc/src/event.rs	46.94%	113 Missing :warning:
...tes/apps/src/lib/node/ledger/shell/testing/node.rs	0.00%	88 Missing :warning:
crates/events/src/extend.rs	74.26%	88 Missing :warning:
...rates/apps/src/lib/node/ledger/shell/governance.rs	14.13%	79 Missing :warning:
crates/events/src/lib.rs	72.68%	62 Missing :warning:
crates/governance/src/event.rs	52.21%	54 Missing :warning:
crates/sdk/src/rpc.rs	0.00%	32 Missing :warning:
crates/state/src/wl_state.rs	0.00%	30 Missing :warning:
...s/apps/src/lib/node/ledger/shell/finalize_block.rs	29.41%	24 Missing :warning:
crates/ibc/src/actions.rs	0.00%	20 Missing :warning:
... and 25 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3141      +/-   ##
==========================================
+ Coverage   59.41%   59.65%   +0.24%     
==========================================
  Files         298      303       +5     
  Lines       92326    93349    +1023     
==========================================
+ Hits        54853    55689     +836     
- Misses      37473    37660     +187     

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[brentstone]

FWIW, currently slashing does not actually involve any balance changes. The tokens are held in the PoS account and they are kept there, only other voting power-related data is manipulated. In PoS, only bonding and withdrawing involve balance changes.

I don't think I know enough about the event emission in general to say whether or not we should still emit events for slashing or if they should strictly be done for balance changes in the context of this PR though.

[sug0]

@brentstone yeah, slashing events were loosely grouped together with other balance change events in this pr, but they're defined as Proof-of-Stake events, rather than Token events. I think it's still useful to emit them in the protocol, as long as we distinguish them from balance change events.

[Fraccaman]

my only comment is that we could move each TokenTransfer event to a static method to avoid having constant string around the code, but we can also do this refactor later. Anything else looks good to me!