zetacore : Identifier naming refactors

[kingpinXD]

This task lists a number of refactors that can to be done to the node code, to make it more readable .

1. Rename all instances of Tss to TSS.
   https://github.com/zeta-chain/zeta-node/blob/5d6891773974fb91100812df629465abbdc0ac0e/testutil/sample/observer.go#L123-L139

2. Rename Identifieriers for store keys to match the value they are storing
   VoterKey -> BallotKey
   AllChainParamsKey -> ChainParamsListKey
   LastBlockObserverCountKey -> LastObserverCountKey
   BallotListKey -> BallotListForHeightKey
   TssFundMigratorInfoKey -> TssFundMigratorKey
   PendingNoncesKeyPrefix -> PendingNoncesListKey
   NonceToCctxKeyPrefix -> NonceToCctxListKey

3. Remove unsed keys

4. We use AuthKeeper for authtypes.AccountKeeper and AuthorityKeeper for authoritytypes.Keeper . Throughout the code . The naming is confusing and should be changed
   We can use
   AccountKeeper for authtypes.AccountKeeper
   AuthorityKeeper for authoritytypes.Keeper