[202412][Partial PR: 18159] cherry-pick generate_topo change only in #18159

[sdszhang]

Cherry-pick generate_topo.py changes in sonic-net/sonic-mgmt#18159 only into 202412 to avoid conflict.

Removed LT2 part of change as it's not needed in 202412.

Description of PR

Summary: Adding LT2 topology and support for generate_topo. We needed to modify the PortChannel name to only use PortChannel10 for multi-asic only to avoid the interface name more than 15 characters which will violate linux interface name.

Fixes # (issue) 32099755

Type of change

• Bug fix

• Testbed and Framework(new/improvement)

• New Test case

  • Skipped for non-supported platforms

• Test case improvement

Back port request

• 202012
• 202205
• 202305
• 202311
• 202405
• 202411

Approach

What is the motivation for this PR?

Add LT2 minigraph changes and topology

How did you do it?

How did you verify/test it?

Any platform specific information?

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

Documentation