Refactor loading of gov proposals for execution

[brentstone]

Describe your changes

Governance proposals were previously loaded every single block, which was a pointless operation. This logic is now coupled more tightly with the execution of the proposals, occurring only once per epoch within a function that loads and then executes.

Proposals are now clearly executed at the beginning of the grace epoch. The previously decoupled logic made it such that proposals were actually executed at the begging of grace_epoch + 1.

This logic is removed from the Shell and reimplemented in the governance crate.

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

v0.32.1

Checklist before merging to draft

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

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 42.85714% with 76 lines in your changes are missing coverage. Please review.

Project coverage is 53.48%. Comparing base (61a0759) to head (3b3ae91).

Files	Patch %	Lines
crates/namada/src/ledger/governance/mod.rs	0.00%	28 Missing ⚠️
crates/governance/src/cli/onchain.rs	0.00%	9 Missing ⚠️
crates/governance/src/cli/validation.rs	0.00%	9 Missing ⚠️
crates/sdk/src/signing.rs	0.00%	8 Missing ⚠️
crates/governance/src/storage/keys.rs	36.36%	7 Missing ⚠️
crates/governance/src/storage/proposal.rs	0.00%	7 Missing ⚠️
crates/governance/src/storage/mod.rs	83.33%	5 Missing ⚠️
crates/light_sdk/src/transaction/governance.rs	0.00%	2 Missing ⚠️
crates/apps/src/lib/bench_utils.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2630      +/-   ##
==========================================
+ Coverage   53.44%   53.48%   +0.03%     
==========================================
  Files         310      310              
  Lines      101574   101604      +30     
==========================================
+ Hits        54288    54340      +52     
+ Misses      47286    47264      -22     

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[adrianbrink]

I think the current behavior is correct. The changes should be activated on the epoch after the grace epoch ends.

[brentstone]

@adrianbrink this is kind of arbitrary though right, since we could just increase the grace_epoch by 1 to achieve the same behavior. I like the idea of renaming to activation_epoch to be more intuitive. I think the code would end up clearer if execution occurred at the grace epoch (or wtv we name it) as well.

[brentstone]

@Fraccaman @adrianbrink what do you think of the changes in 9a354f4? I think renaming makes things much clearer to understand upon reading code and in general going forward, but we can remove this commit if there are objections.

[tzemanovic]

looks like the e2e tests are actually broken here

[tzemanovic]

looks like the e2e tests are actually broken here

it just needed make -C wasm_for_tests/wasm_source (can be done on merge)