[Snappi] Adding BGP Performance Testcases for T2

[selldinesh]

Description of PR

Summary:This PR includes the scripts for testcase 1.1 from https://github.com/kamalsahu0001/sonic-mgmt/blob/Work-T2-Convergence/docs/testplan/Convergence%20measurement%20in%20data%20center%20networks.md Fixes # (issue)

Type of change

• [ ] Bug fix
• [ ] Testbed and Framework(new/improvement)
• [ ] Test case(new/improvement)

Back port request

• [ ] 202012
• [ ] 202205
• [ ] 202305
• [ ] 202311
• [ ] 202405

Approach

What is the motivation for this PR?

Contribute the scripts for BGP Performance Testcases

How did you do it?

We created connection between T1 and T2 setup and executed our outbound testcase

How did you verify/test it?

This was tested on T1 and T2 chassis

Any platform specific information?

Supported testbed topology if it's a new test case?

Documentation