Delegation Staking Limits

[iramiller]

Description

This PR adds hooks that prevent stake concentration for validators.

closes: #1322

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[codecov]

Codecov Report

Merging #1331 (d5dee04) into main (bfb3b38) will decrease coverage by 0.07%.
The diff coverage is 30.35%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1331      +/-   ##
==========================================
- Coverage   59.00%   58.93%   -0.07%     
==========================================
  Files         196      197       +1     
  Lines       24729    24783      +54     
==========================================
+ Hits        14591    14606      +15     
- Misses       9046     9085      +39     
  Partials     1092     1092              

Impacted Files	Coverage Δ
internal/handlers/staking_restrictions_hooks.go	27.77% <27.77%> (ø)
app/app.go	87.51% <100.00%> (ø)

[iramiller]

To verify:

make clean build localnet-start
./build/provenanced -t --home ./build/node1/ keys list  

Note address: tp173f8e97r2uft42ltsdhjzz7e8qzv0pr4cxlkd9

./build/provenanced -t --home ./build/node0/ q staking validators

Note address: tpvaloper173f8e97r2uft42ltsdhjzz7e8qzv0pr480zzcq

./build/provenanced -t --home ./build/node1/ tx staking delegate tpvaloper173f8e97r2uft42ltsdhjzz7e8qzv0pr480zzcq 17999999965710000000nhash --from tp173f8e97r2uft42ltsdhjzz7e8qzv0pr4cxlkd9 --chain-id chain-local --fees 38100000000nhash

Note the failure message: 'failed to execute message; message index: 0: validator bonded tokens of 18000000365710000000 exceeds max of 5940000120684300000 (33.0%) for 4 validators: invalid request'

./build/provenanced -t --home ./build/node1/ tx staking delegate tpvaloper173f8e97r2uft42ltsdhjzz7e8qzv0pr480zzcq 10000000nhash --from tp173f8e97r2uft42ltsdhjzz7e8qzv0pr4cxlkd9 --chain-id chain-local --fees 38100000000nhash

Note that this smaller delegation is successful.

[SpicyLemon]

Needs changelog entry, but looks good.

[egaxhaj]

codecov has dropped a bit

[iramiller]

codecov has dropped a bit

This is expected... the hooks are not reasonable to unit test due to lack of mock structure (especially given the timeframe on release) which is why there is a manual test case on this issue. Not ideal certainly.