Change the consensus reward method

[zemyblue]

We need to change the consensus reward method.
But this method is implemented in the Cosmos-SDK, therefore we need to check how to do.

[zemyblue]

Tendermint's basic reward distribution system is in Cosmos-SDK, but even if only voters elected from this logic transmit voting power and distribute it, it is distributed in proportion to the staking value, so I think there is no problem using the basic system.

Next data is part of the reward distribution simulation result.

idx	staking	selected	total vp	sum reward	reward rate / staking rate
63	4516370	4367	5719675	4184.35636	0.996222
79	4519584	4404	5767727	4220.4768	1.004107
94	4563578	4507	5923224	4337.15965	1.02192
62	4569419	4385	5764600	4219.94265	0.993031
46	4572028	4461	5841895	4271.59498	1.004612
60	4596592	4522	5949945	4352.55576	1.018182
69	4618147	4484	5891579	4315.00374	1.004686
67	4625211	4539	5983580	4378.79435	1.017982
92	4639030	4493	5911955	4326.83215	1.002905
81	4651790	4493	5921516	4325.54521	0.999857
54	4653399	4504	5948674	4355.94341	1.006535
83	4653986	4502	5938795	4345.49715	1.003995
80	4673362	4567	6040196	4417.48631	1.016396
68	4680899	4431	5849880	4279.31643	0.98302
50	4682156	4521	5980407	4377.57473	1.005321

When I simulate the basic reward distribution system of Cosmos-SDK, the total reward of each validator is fair. So, I think it is good, we don't need to change.