Add signatures result in transaction output

[amishas157]

PR Checklist

PR Structure

• This PR has reasonably narrow scope (if not, break it down into smaller PRs).
• This PR avoids mixing refactoring changes with feature changes (split into two PRs
  otherwise).
• This PR's title starts with the jira ticket associated with the PR.

Thoroughness

• This PR adds tests for the most critical parts of the new functionality or fixes.
• I've updated the README with the added features, breaking changes, new instructions on how to use the repository. I updated the description of the fuction with the changes that were made.

Release planning

• I've decided if this PR requires a new major/minor/patch version accordingly to
  semver, and I've changed the name of the BRANCH to release/_ , feature/_ or patch/* .

What

This PR adds export of signatures field in history_transactions table.

Why

There are instances when a payment is initiated by child account, however the balance is cut from parent account. To verify that parent account adds signatures to those payment, we require this feature.

Known limitations

None. Signatures is added as repeated string. To use it downstream, we would need to unnest it. However, there are no alternatives of it.

[amishas157]

Test Results:

1. Local

root@94c16c371f6a:/etl/data# stellar-etl export_transactions --start-ledger 4729339 --end-ledger 4729939 --output exported_transactions.txt
INFO[2024-07-29T17:51:53.229Z] Number of bytes written: 9607                 pid=20
INFO[2024-07-29T17:51:53.231Z] {"attempted_transforms":5,"failed_transforms":0,"successful_transforms":5}  pid=20
INFO[2024-07-29T17:51:53.231Z] No cloud provider specified for upload. Skipping upload.  pid=20
root@94c16c371f6a:/etl/data# head exported_transactions.txt
root@94c16c371f6a:/etl/data# head exported_transactions.txt
{"account":"GDPBVCYEQCVPE66UQPFSGCF6WCFYQC4CW7BESWR4DVD7HUI3FELKUT4K","account_sequence":18020046391476225,"closed_at":"2016-06-08T21:13:08Z","created_at":"2016-06-08T21:13:08Z","extra_signers":null,"fee_charged":100,"id":20312356336701440,"inclusion_fee_bid":0,"inclusion_fee_charged":0,"ledger_bounds":"","ledger_sequence":4729339,"max_fee":100,"memo":"3598160","memo_type":"MemoTypeMemoText","min_account_sequence":null,"min_account_sequence_age":null,"min_account_sequence_ledger_gap":null,"non_refundable_resource_fee_charged":0,"operation_count":1,"refundable_resource_fee_charged":0,"rent_fee_charged":0,"resource_fee":0,"resource_fee_refund":0,"signatures":["pwvX5/Zr91oRUaijPXdtUQ6zNY/w38sKVoUxO7CcAdm6OsZEuPGT5hXo3iF2dz5ArE7LWz3gsjGkmrSKgIqDCA=="],"soroban_resources_instructions":0,"soroban_resources_read_bytes":0,"soroban_resources_write_bytes":0,"successful":false,"time_bounds":"","transaction_hash":"dfce4ce6818623afb10a85f0ad51f877ad2b6627dcdaf6f4655de981fee6fbca","transaction_result_code":"TransactionResultCodeTxFailed","tx_envelope":"AAAAAN4aiwSAqvJ71IPLIwi+sIuIC4K3wklaPB1H89EbKRaqAAAAZABABSMAAAABAAAAAAAAAAEAAAAHMzU5ODE2MAAAAAABAAAAAAAAAAEAAAAAjNsoSdqPFb2bmzzfj3buFDSVfgawK5btZGeeQ95hGZ8AAAAAAAAAC6hnkIYAAAAAAAAAARspFqoAAABApwvX5/Zr91oRUaijPXdtUQ6zNY/w38sKVoUxO7CcAdm6OsZEuPGT5hXo3iF2dz5ArE7LWz3gsjGkmrSKgIqDCA==","tx_fee_meta":"AAAAAgAAAAMAQAUjAAAAAAAAAADeGosEgKrye9SDyyMIvrCLiAuCt8JJWjwdR/PRGykWqgAAAAu0U1KGAEAFIwAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAEASCn7AAAAAAAAAADeGosEgKrye9SDyyMIvrCLiAuCt8JJWjwdR/PRGykWqgAAAAu0U1IiAEAFIwAAAAEAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAA==","tx_meta":"AAAAAgAAAAAAAAAAAAAAAA==","tx_result":"AAAAAAAAAGT/////AAAAAQAAAAAAAAAB/////gAAAAA="}
{"account":"GDPBVCYEQCVPE66UQPFSGCF6WCFYQC4CW7BESWR4DVD7HUI3FELKUT4K","account_sequence":18020046391476226,"closed_at":"2016-06-08T21:16:52Z","created_at":"2016-06-08T21:16:52Z","extra_signers":null,"fee_charged":100,"id":20312622624673792,"inclusion_fee_bid":0,"inclusion_fee_charged":0,"ledger_bounds":"","ledger_sequence":4729401,"max_fee":100,"memo":"3598160","memo_type":"MemoTypeMemoText","min_account_sequence":null,"min_account_sequence_age":null,"min_account_sequence_ledger_gap":null,"non_refundable_resource_fee_charged":0,"operation_count":1,"refundable_resource_fee_charged":0,"rent_fee_charged":0,"resource_fee":0,"resource_fee_refund":0,"signatures":["r03h1GsEVf3WBEY5wrC0rIJ6bJQTcmhNnQA/Mlc/560iC0Ckvc/EPGSVkCPrRyeM9zQySp4nDRud1R6B3yooBA=="],"soroban_resources_instructions":0,"soroban_resources_read_bytes":0,"soroban_resources_write_bytes":0,"successful":false,"time_bounds":"","transaction_hash":"a9bb0b83dc8b1735a11ede37aced567faf37b3f3004f29b5e30963d68e6ffcfe","transaction_result_code":"TransactionResultCodeTxFailed","tx_envelope":"AAAAAN4aiwSAqvJ71IPLIwi+sIuIC4K3wklaPB1H89EbKRaqAAAAZABABSMAAAACAAAAAAAAAAEAAAAHMzU5ODE2MAAAAAABAAAAAAAAAAEAAAAAjNsoSdqPFb2bmzzfj3buFDSVfgawK5btZGeeQ95hGZ8AAAAAAAAAC6hnkCIAAAAAAAAAARspFqoAAABAr03h1GsEVf3WBEY5wrC0rIJ6bJQTcmhNnQA/Mlc/560iC0Ckvc/EPGSVkCPrRyeM9zQySp4nDRud1R6B3yooBA==","tx_fee_meta":"AAAAAgAAAAMASCn7AAAAAAAAAADeGosEgKrye9SDyyMIvrCLiAuCt8JJWjwdR/PRGykWqgAAAAu0U1IiAEAFIwAAAAEAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAEASCo5AAAAAAAAAADeGosEgKrye9SDyyMIvrCLiAuCt8JJWjwdR/PRGykWqgAAAAu0U1G+AEAFIwAAAAIAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAA==","tx_meta":"AAAAAgAAAAAAAAAAAAAAAA==","tx_result":"AAAAAAAAAGT/////AAAAAQAAAAAAAAAB/////gAAAAA="}

2. BigQuery