* Porting app.go based sdk 0.43.0

* fix: sdk v0.43.0 marshaling changes

* fix: test account, mint utils

* fix: replace deprecated json cli codec

* feat: add migration codes for ReserveAccIndex

* chore: remove useless comment

* chore: refactoring test_helpers

* chore: fix lint appendAssign

* chore: refact duplicated function

* fix: WIP update docs

* docs: add changelog

* fix: refactor app.go