More staking queries

[rigelrozanski]

There is limited querying of the persisted state of staking right now should be able to query:

• list of all validators
• list of all candidates
• list of delegations to a validator/candidate
• list of all validators which a delegator has delegated too
• current state of the "pool"
• global values for the params (advanced)

Blocked on having support for range queries in the app-query-helper functions

[rigelrozanski]

related: #871

[ebuchman]

@rigelrozanski can we update this issue and/or possible close it ?

[rigelrozanski]

Nothing has changed on this issue, but it is still relevant and should be updated: can solve after unbonding

[fedekunze]

@rigelrozanski @ebuchman most of the checkboxes have been implemented in #1880 and #2000 . I'll close and create new issues for the remaining queries