unify util tsdk and store packages

[robert-zaremba]

Description

test/util/store.go and test/tsdk/store.go have duplicated functionality. This PR unifies them.
Once we will remove GB, the test/util package will be removed as well.

[codecov]

Codecov Report

Merging #2038 (ed33f9f) into main (7f05ad4) will decrease coverage by 7.96%.
The diff coverage is 47.14%.

❗ Current head ed33f9f differs from pull request most recent head b69a9d0. Consider uploading reports for the commit b69a9d0 to get more accurate results

@@            Coverage Diff             @@
##             main    #2038      +/-   ##
==========================================
- Coverage   75.38%   67.43%   -7.96%     
==========================================
  Files         100      123      +23     
  Lines        8025     9434    +1409     
==========================================
+ Hits         6050     6362     +312     
- Misses       1589     2605    +1016     
- Partials      386      467      +81     

Impacted Files	Coverage Δ
util/store/unmarshal.go	0.00% <0.00%> (ø)
x/incentive/codec.go	47.82% <ø> (+9.89%)	⬆️
x/incentive/keeper/hooks.go	0.00% <0.00%> (ø)
x/incentive/keeper/invariants.go	0.00% <0.00%> (ø)
x/leverage/keeper/incentive.go	0.00% <0.00%> (ø)
x/leverage/types/token.go	77.27% <ø> (ø)
x/oracle/keeper/hooks.go	95.65% <ø> (ø)
x/ugov/keeper/msg_server.go	0.00% <0.00%> (ø)
x/ugov/keeper/query_server.go	0.00% <0.00%> (ø)
x/uibc/quota/keeper/genesis.go	0.00% <0.00%> (-100.00%)	⬇️
... and 41 more

... and 2 files with indirect coverage changes

[gsk967]

LGTM