Fixes to make hermes work with non-gaiad custom chains (e.g. starport)

[andynog]

Closes:

• Support for chains that don't have "cosmos" as hrp for bech32 address #416
• Account number hardcoded #752

Description

This PR implements fixes to allow hermes relay packets between two non-gaiad based chains.

These changes were tested against two starport v0.15.0 (supports cosmos-sdk v0.42.1). These starport chains have custom account prefix addresses (not cosmos) such as chainb1pnv0elanhs8qcq2sst0jssak8magjpj3ggq45x

This PR also fixes an issue where the account number is not 0. For example the starport chains have multiple accounts (e.g. validator and bob). So using bob account key in the relayer would make the transactions fail because that account number is 1 in the key store. After the fix, it works now because the account number is dynamically fetched from the chain using grpc (same logic that gets the account sequence to submit transaction).

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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.

[codecov-io]

Codecov Report

Merging #753 (a25d544) into master (b1b37f5) will increase coverage by 30.1%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #753      +/-   ##
=========================================
+ Coverage    13.6%   43.8%   +30.1%     
=========================================
  Files          69     159      +90     
  Lines        3752   10427    +6675     
  Branches     1374       0    -1374     
=========================================
+ Hits          513    4572    +4059     
- Misses       2618    5855    +3237     
+ Partials      621       0     -621     

Impacted Files	Coverage Δ
...application/ics20_fungible_token_transfer/error.rs	0.0% <ø> (ø)
...ion/ics20_fungible_token_transfer/msgs/transfer.rs	0.0% <ø> (ø)
..._transfer/relay_application_logic/send_transfer.rs	0.0% <ø> (ø)
modules/src/events.rs	0.0% <ø> (ø)
modules/src/handler.rs	100.0% <ø> (ø)
modules/src/ics02_client/client_consensus.rs	55.8% <ø> (ø)
modules/src/ics02_client/client_def.rs	33.0% <ø> (ø)
modules/src/ics02_client/client_state.rs	65.1% <ø> (ø)
modules/src/ics02_client/client_type.rs	79.1% <ø> (+31.5%)	⬆️
modules/src/ics02_client/context.rs	100.0% <ø> (ø)
... and 255 more

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[ancazamfir]

lgtm, thanks Andy!

[romac]

Looks good, I just have one question but it does not block from merging.

[romac]

Is this supposed to stay hardcoded forever or do we eventually want to make this configurable/dynamic?

[andynog]

@romac I believe this should be dynamic, we can have a default value but should allow the value to be passed as a parameter, I had opened a separate issue for that #754