Return PortId information in query_channels

[soareschen]

Closes: #840

Description

Before:

$ hermes query channels ibc-0
Success: [
    ChannelId(
        "channel-0",
    ),
]

$ hermes -j query channels ibc-0
{"result":["channel-0"],"status":"success"}

After:

$ hermes query channels ibc-0
Success: [
    PortChannelId {
        channel_id: ChannelId(
            "channel-0",
        ),
        port_id: PortId(
            "transfer",
        ),
    },
]

$ hermes -j query channels ibc-0
{"result":[{"channel_id":"channel-0","port_id":"transfer"},{"channel_id":"channel-1","port_id":"transfer"},{"channel_id":"channel-2","port_id":"transfer"}],"status":"success"}

_

For contributor use:

• Updated the Unreleased section of CHANGELOG.md with the issue.
• If applicable: Unit tests written, added test to CI.
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Updated relevant documentation (docs/) and code comments.
• Re-reviewed Files changed in the Github PR explorer.

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This change is 

[ancazamfir]

Looks good, thanks @soareschen! Could you please update CHANGELOG.md file?

[codecov-commenter]

Codecov Report

Merging #861 (44f2e91) into master (615649a) will decrease coverage by 0.0%.
The diff coverage is 0.0%.

❗ Current head 44f2e91 differs from pull request most recent head ba92ebd. Consider uploading reports for the commit ba92ebd to get more accurate results

@@           Coverage Diff            @@
##           master    informalsystems/hermes#861     +/-   ##
========================================
- Coverage    43.5%   43.4%   -0.1%     
========================================
  Files         170     170             
  Lines       12641   12660     +19     
========================================
  Hits         5507    5507             
- Misses       7134    7153     +19     

Impacted Files	Coverage Δ
modules/src/ics24_host/identifier.rs	80.6% <ø> (ø)
relayer/src/chain.rs	0.0% <ø> (ø)
relayer/src/chain/cosmos.rs	0.0% <0.0%> (ø)
relayer/src/chain/mock.rs	63.9% <0.0%> (ø)
relayer/src/keyring.rs	0.0% <0.0%> (ø)
relayer/src/keyring/errors.rs	0.0% <0.0%> (ø)
relayer-cli/src/commands/keys/restore.rs	0.0% <0.0%> (ø)

---

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[soareschen]

I have added a PortChannelId type to bundle together PortId and ChannelId and have its own JSON serialization. I will create a separate PR to work on cosmos/ibc-rs#84 to refactor other uses of (PortId, ChannelId) to PortChannelId.

[soareschen]

@romac shall we merge this?