feat: implement fast-liquidation

[toteki]

Follows up on the proto PR. Will include feature and tests.

[codecov]

Codecov Report

Merging #2106 (1925266) into main (7f05ad4) will decrease coverage by 0.39%.
The diff coverage is 77.57%.

@@            Coverage Diff             @@
##             main    #2106      +/-   ##
==========================================
- Coverage   75.38%   75.00%   -0.39%     
==========================================
  Files         100      127      +27     
  Lines        8025     9776    +1751     
==========================================
+ Hits         6050     7332    +1282     
- Misses       1589     1957     +368     
- Partials      386      487     +101     

Impacted Files	Coverage Δ
ante/spam_prevention.go	75.92% <ø> (ø)
x/incentive/codec.go	47.82% <ø> (+9.89%)	⬆️
x/incentive/keeper/invariants.go	0.00% <0.00%> (ø)
x/leverage/client/tests/suite.go	100.00% <ø> (ø)
x/leverage/client/tests/tests.go	100.00% <ø> (ø)
x/leverage/keeper/borrows.go	77.58% <ø> (-0.99%)	⬇️
x/leverage/keeper/collateral.go	72.72% <ø> (-0.16%)	⬇️
x/leverage/keeper/errors.go	100.00% <ø> (ø)
x/leverage/keeper/exchange_rate.go	72.72% <ø> (ø)
x/leverage/keeper/genesis.go	87.23% <ø> (ø)
... and 62 more

... and 25 files with indirect coverage changes

[robert-zaremba]

Given that there are few risks with the approach (liquidator going into danger zone, liquidator getting a debt to pay, which is not paid automatically), let's make sure we:

• document this in the README (or other file, and link it to README).
• update the proto comments
• update CLI (just saying that liquidator will take borrowers debt, which later the liquidator will need to pay).
• also let's rename Fast Liquidation to Leverage Liquidation (good name suggestion by Adam)

I will add few follow up tasks to linear

[robert-zaremba]

lgtm. Left few docs suggestions.

[toteki]

All suggestions committed - moving to merge