1630 ballot operation support in contract API (#2050)

* added estimate and contract ballot operation support

* added rpc contract provider for ballot op

* updated implementation and added docs

* added property in OperationContentsAndResultBallot and added unit test

* remove metadata property from ballot

* addressed PR comments

* updated yarn and package-lock

* cleaned up comments and switched out async for promise in op emitter

* removed unnecessary line break

docs/ballot.md

@@ -0,0 +1,23 @@
+---
+title: Ballot Operation
+id: ballot
+author: Davis Sawali
+---
+
+The `Ballot` operation allows delegates to cast one `Yay`, `Nay`, or `Pass` ballot on a selected proposal. Delegates are only able to cast their votes during the **Exploration period** and the **Promotion period**
+
+## Examples
+The `Ballot` operation is currently available in the Contract API, and can be used as such:
+```typescript
+const op = await Tezos.contract.ballot({
+  proposal: 'PROPOSAL_HASH',
+  ballot: 'BALLOT_VOTE_STRING'
+});
+
+await op.confirmation();
+```
+- `proposal` is the proposal hash string that you (a delegate) would like to point your ballot towards. Information on the current proposal can be obtained by calling [this RPC endpoint](https://tezos.gitlab.io/alpha/rpc.html#get-block-id-votes-current-proposal). Alternatively, you could also get the proposal hash by using Taquito's RPC Client method `RpcClient.getCurrentProposal`. For more information on the `RpcClient` refer to [this document](https://tezostaquito.io/docs/rpc_package/)
+- `ballot` is your ballot vote (`yay`, `nay`, or `pass`)
+
+
+For more information in regards to the Amendment (and Voting) Process refer to [this document](https://tezos.gitlab.io/alpha/voting.html)