Gaia is removed from cosmos-sdk repository.
Few changes were required to make sure no packages depend on gaia subpackages.
CI config is amended accordingly.
Unnecessary targets are removed from Makefile.
Simulations run through a lightweight version of gaia renamed to simapp.
Closes: #4104
* Remove shares concept from unbonding and redelegation
* Remove redundant staking REST type declerations
* Rename staking REST request types
* Fix slashing tests
* Fix staking tests
* Fix integration tests
* Add safety checks for when validator tokens are zero
* Attempt to fix simulation
* Add pending log entry
* Update docs
* Implement and use SharesFromTokens
* Rename ShareTokens and ShareTokensTruncated
* Rename Delegation to Amount in DelegateRequest
* Implement and use SharesFromTokensTruncated
* Update MsgDelegate to use Amount instead of Value
* Use constructors in staking sim messages
* Implement and use ValidateUnbondAmount