feat: script that opens concurrent intents

[kss-t1]

Description

script that sends many intents concurrently. this is first iteration that I wrote&tested within my timebox. I could improve it by:

• using multiple private keys
• using multiple RPCs

Motivation and Context

we need it to test reliability of the bridge when sending concurrent intents. some of our partners (esp. Eco) are interested in such a metric

How Has This Been Tested?

on local, against mainnet

Types of changes (remove all unchecked types)

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Style (style only changes)
• Docs
• Refactor (code that does not add new functionality nor fixes a bug)

Checklist:

• If my change requires a change to the documentation, I have updated the documentation accordingly, and in either case, have checked this box to attest to my assessment of this requirement with regard to my change.
• If my change requires additions or updates to any deployment scripts to ensure that the protocol is functional (Makefile, Dockerfile, Forge Script, etc.), I have made these changes, and in either case, have checked this box to attest to my assessment of this requirement with regard to my change.
• If my change requires additional test coverage, I have created those tests accordingly, and in either case, have checked this box to attest to my assessment of this requirement with regard to my change.