clang-tidy: Add config to enforce naming style

[w1ldptr]

What?

Create a config file for clang-tidy tool in order to enforce naming style of types, functions, and variables according to NIXL code style.

Why?

Both internal and external contributors have often been naming types, functions, and variables incorrectly. Moreover, due to complex NIXL naming conventions these mistakes often slip past code review.

How?

Clang-tidy is a tool readily available in Ubuntu and other distro's repositories similarly to clang-format that is already used by NIXL. Excerpt from the tool output with provided config on a NIXL source:

../../home/vladbu/src/nixl/src/plugins/ucx/ucx_backend.cpp:236:59: warning: invalid case style for parameter 'devId' [readability-identifier-naming]
  236 | int nixlUcxEngine::vramUpdateCtx(void *address, uint64_t  devId, bool &restart_reqd)
      |                                                           ^~~~~
      |                                                           dev_id
  237 | {
  238 |     int ret;
  239 |     bool was_updated;
  240 |
  241 |     restart_reqd = false;
  242 |
  243 |     if(!cuda_addr_wa) {
  244 |         // Nothing to do
  245 |         return 0;
  246 |     }
  247 |
  248 |     ret = cudaCtx->cudaUpdateCtxPtr(address, devId, was_updated);
      |                                              ~~~~~
      |                                              dev_id
../../home/vladbu/src/nixl/src/plugins/ucx/ucx_backend.cpp:288:14: warning: invalid case style for method 'is_complete' [readability-identifier-naming]
  288 |         bool is_complete() const { return _completed; }
      |              ^~~~~~~~~~~
      |              isComplete
../../home/vladbu/src/nixl/src/plugins/ucx/ucx_backend.cpp:322:12: warning: invalid case style for struct 'Notif' [readability-identifier-naming]
  322 |     struct Notif {
      |            ^~~~~
      |            notif
  323 |             std::string agent;
  324 |             nixl_blob_t payload;
  325 |             Notif(const std::string& remote_agent, const nixl_blob_t& msg)
      |             ~~~~~
      |             notif
  326 |                     : agent(remote_agent), payload(msg) {}
  327 |     };
  328 |     std::optional<Notif> notif;
      |                   ~~~~~
      |                   notif

[github-actions]

👋 Hi w1ldptr! Thank you for contributing to ai-dynamo/nixl.

Your PR reviewers will review your contribution then trigger the CI to test your changes.

🚀

[w1ldptr]

/build

[w1ldptr]

/build

[w1ldptr]

/ok to test d8254e0