Remove mentions of shares from client returns

[jackzampolin]

Ref: luniehq/lunie#1931

[faboweb]

Summing up:
Clients should not care about the internal concept of shares.
I as a user only want to know how many tokens I have delegated to a validator so I can quickly evaluate how much value I have delegated.
Same: I as a user want to withdraw x tokens I have delegated to a validator.

Therefor in the CLI and REST interface displaying and withdrawing (and redelegation?!) of stake should only happen in tokens. Those tokens are then converted into and from shares internally.

[rigelrozanski]

makes ample sense - some consideration needs to given based truncation which may occur based on values of shares etc.. but I don't think it's anything unmanageable