Adjacency List

[adityaranigaon]

Implemented Adjacency List in TriangleMesh:

1. Write C++ func=ons:
   std::pair<core::Tensor, core::Tensor>
   open3d::t::geometry::TriangleMesh::ComputeAdjacencyList();
   File: cpp/open3d/t/geometry/TriangleMesh.cpp

2. Write the Python binding:
   open3d.t.geometry.TriangleMesh.compute_adjacency_list()
   File: cpp/pybind/t/geometry/trianglemesh.cpp

3. Write C++ and python unit tests integrated with Open3D's unit test system.
   Files: cpp/tests/t/geometry/TriangleMesh.cpp and
   python/test/t/geometry/test_trianglemesh.py

[update-docs]

Thanks for submitting this pull request! The maintainers of this repository would appreciate if you could update the CHANGELOG.md based on your changes.

[ssheorey]

Moved to PR #7094