feat: mint calculator

[robert-zaremba]

Description

Adding cusotmized InflationCalculationFn and a inflation Calculator type.
Should be used in #2145 to avoid module fork.

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Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• added appropriate labels to the PR
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

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your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[codecov]

Codecov Report

Merging #2159 (1f6f280) into main (7f05ad4) will decrease coverage by 4.78%.
The diff coverage is 80.60%.

@@            Coverage Diff             @@
##             main    #2159      +/-   ##
==========================================
- Coverage   75.38%   70.61%   -4.78%     
==========================================
  Files         100      147      +47     
  Lines        8025    11197    +3172     
==========================================
+ Hits         6050     7907    +1857     
- Misses       1589     2750    +1161     
- Partials      386      540     +154     

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/incentive/keeper/update.go	52.11% <ø> (ø)
x/incentive/keys.go	100.00% <ø> (ø)
x/incentive/msgs.go	77.41% <ø> (-0.81%)	⬇️
x/incentive/params.go	89.28% <ø> (-10.72%)	⬇️
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	75.93% <ø> (-2.64%)	⬇️
... and 55 more

... and 52 files with indirect coverage changes