Added ChannelId to MsgChannelOpenInitResponse (#848)

## Description
added ChannelId to MsgChannelOpenInitResponse
this is needed for distribution within interchain security

Also my go imports didn't like go metrics so I had to add the go-metrics alias

Supersedes: #839

Quote from @AdityaSripal
Context for the other folks reviewing: This is a problem in general not just for CCV. But currently, in CCV we want to initiate a transfer channel and know what the channelID is.

So if we want to do this as part of third-party module logic, it's currently impossible with the codebase. Since, if you try to use channelKeeper directly you will need portCapability; and a third party module will not have transfer's portCapability.

So we have to use the MsgServer, but the response doesn't include the channelID which we need since then we want to send transfer packets over the established channel.

So this is going to be an issue for any third-party module that wants to initialize a channel of a different IBC application and then use that channel to send packets over

---

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checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

- [x] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [x] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [x] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [ ] Wrote unit and integration [tests](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#testing)
- [x] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [x] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [x] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
- [x] Re-reviewed `Files changed` in the Github PR explorer
- [ ] Review `Codecov Report` in the comment section below once CI passes

(cherry picked from commit 7b7eb9f)

CHANGELOG.md

@@ -43,6 +43,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### API Breaking
 
+* (channel( [\#848](https://github.com/cosmos/ibc-go/pull/848) Added `ChannelId` to MsgChannelOpenInitResponse
 * (testing( [\#813](https://github.com/cosmos/ibc-go/pull/813) The `ack` argument to the testing function `RelayPacket` has been removed as it is no longer needed.
 * (testing) [\#774](https://github.com/cosmos/ibc-go/pull/774) Added `ChainID` arg to `SetupWithGenesisValSet` on the testing app. `Coordinator` generated ChainIDs now starts at index 1
 * (transfer) [\#675](https://github.com/cosmos/ibc-go/pull/675) Transfer `NewKeeper` now takes in an ICS4Wrapper. The ICS4Wrapper may be the IBC Channel Keeper when ICS20 is not used in a middleware stack. The ICS4Wrapper is required for applications wishing to connect middleware to ICS20.

docs/ibc/proto-docs.md

@@ -1888,6 +1888,11 @@ is called by a relayer on Chain A.
 MsgChannelOpenInitResponse defines the Msg/ChannelOpenInit response type.
 
 
+| Field | Type | Label | Description |
+| ----- | ---- | ----- | ----------- |
+| `channel_id` | [string](#string) |  |  |
+
+
 
 
 

modules/core/keeper/msg_server.go

@@ -3,7 +3,8 @@ package keeper
 import (
 	"context"
 
-	"github.com/armon/go-metrics"
+	metrics "github.com/armon/go-metrics"
+
 	"github.com/cosmos/cosmos-sdk/telemetry"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
@@ -191,7 +192,9 @@ func (k Keeper) ChannelOpenInit(goCtx context.Context, msg *channeltypes.MsgChan
 	// Write channel into state
 	k.ChannelKeeper.WriteOpenInitChannel(ctx, msg.PortId, channelID, msg.Channel.Ordering, msg.Channel.ConnectionHops, msg.Channel.Counterparty, msg.Channel.Version)
 
-	return &channeltypes.MsgChannelOpenInitResponse{}, nil
+	return &channeltypes.MsgChannelOpenInitResponse{
+		ChannelId: channelID,
+	}, nil
 }
 
 // ChannelOpenTry defines a rpc handler method for MsgChannelOpenTry.

proto/ibc/core/channel/v1/tx.proto

@@ -54,7 +54,9 @@ message MsgChannelOpenInit {
 }
 
 // MsgChannelOpenInitResponse defines the Msg/ChannelOpenInit response type.
-message MsgChannelOpenInitResponse {}
+message MsgChannelOpenInitResponse {
+  string channel_id = 1 [(gogoproto.moretags) = "yaml:\"channel_id\""];
+}
 
 // MsgChannelOpenInit defines a msg sent by a Relayer to try to open a channel
 // on Chain B. The version field within the Channel field has been deprecated. Its