fix(oracle): avg params storage.

[robert-zaremba]

Description

• v6.1 upgrade handler with code to set AvgParams
• remove the v6.0.2 fallback to use default AvgParams
• fix the key scheme by moving the AvgParams store key from params.go (which is dedicated for the x/param spaces) to keys.go.

[codecov]

Codecov Report

Merging #2260 (726fbb2) into main (7f05ad4) will decrease coverage by 4.99%.
Report is 239 commits behind head on main.
The diff coverage is 83.60%.

@@            Coverage Diff             @@
##             main    #2260      +/-   ##
==========================================
- Coverage   75.38%   70.40%   -4.99%     
==========================================
  Files         100      168      +68     
  Lines        8025    12644    +4619     
==========================================
+ Hits         6050     8902    +2852     
- Misses       1589     3143    +1554     
- Partials      386      599     +213     

Files Changed	Coverage Δ
ante/spam_prevention.go	75.92% <ø> (ø)
cmd/ibc_denom/main.go	0.00% <0.00%> (ø)
util/coin/coin.go	12.50% <0.00%> (ø)
util/sdkutil/msg.go	0.00% <0.00%> (ø)
x/incentive/codec.go	47.82% <ø> (+9.89%)	⬆️
x/incentive/keeper/bond.go	92.50% <ø> (ø)
x/incentive/keeper/genesis.go	40.90% <ø> (ø)
x/incentive/keeper/grpc_query.go	59.18% <ø> (ø)
x/incentive/keeper/hooks.go	50.00% <ø> (ø)
x/incentive/keeper/invariants.go	0.00% <ø> (ø)
... and 49 more

... and 86 files with indirect coverage changes

[gsk967]

LGTM