[BCI-1477] Implement cosmos specific txn type for generic txm

[yongkangc]

This PR implements implements chain specific transaction type based on the generic Transaction manager transaction interface.

Context:

• In order for cosmos to make use of generic txm logic, it requires to implement the TxRequest type and encoding/decoding methods are needed.
• The EVM has a similar implementation here: https://github.com/smartcontractkit/chainlink/blob/7b57ad4c15a2286377ba8cb8775d6c7aa2796251/core/chains/evm/txmgr/models.go#L16-L17

Changes:

• bumping chainlink-relay to make use of the generic Txn Types in the PR [BCI-1792] Moved over TxAttemptBuilder and Tx interfaces chainlink-common#154
• implemented chain specific transaction types and encoding/decoding methods.
• tests

Note:

• Not sure if we would want to merge this, as this PR is dependent on Txn-types on chainlink-relay in the PR [BCI-1792] Moved over TxAttemptBuilder and Tx interfaces chainlink-common#154. However we are still in the middle of persistence layer proposal, and sqlx dependency has yet to be extracted out. See comment for the discussion.
  • Might have to consult @aalu1418 for path forward.

References:

• Design docs
• Tickets: https://smartcontract-it.atlassian.net/browse/BCI-1477

[prashantkumar1982]

Just curious, why do we use 32-bytes, and not just []bytes?
As in this comment, I don't think the Hashable interface enforces us to have [32]byte.

Using just []byte would allow us to use sdk.Address directly.

[yongkangc]

we would need to use 32-bytes because it needs to conform to the comparable constraint implemented by the hashable interface. Would update the comment to make this clearer

[prashantkumar1982]

If I understand this correctly, does this remove all trailing 0s from the address?

What if the actual cosmos address had 0s in the address?
Or, I assume cosmos address wouldn't have 0s(unicode 0s, not string of "0") in the address, so its safe to do this?

[yongkangc]

If I understand this correctly, does this remove all trailing 0s from the address?

yup, this will remove trailing zeros from the addresses.

What if the actual cosmos address had 0s in the address?

The cosmos addresses can have 0s in the address, but it would not have unicode 0s

Cosmos addresses are derived from public keys using the Bech32 encoding scheme. Because Bech32 uses a specific set of 32 characters, the Unicode null character (U+0000) would not be possible.

Reference:
Bech32 is an encoding scheme used to encode SegWit addresses and Lightning invoices. The Bech32 alphabet contains 32 characters, including lowercase letters a-z and the numbers 0-9, excluding the number 1 and the letters ‘b’, ‘i’, ‘o’ to avoid reader confusion. Bech32 also includes an error detection mechanism.

[yongkangc]

The Staging branch has been changed to cosmos-generic-txm-staging