Define macros for LLNDK versioning

__INTRODUCED_IN_LLNDK(vendor_api_level) is for the LLNDK APIs
introduced in the vendor_api_level. It is ignored for non-vendor
modules.

API_LEVEL_AT_LEAST(sdk_api_level, vendor_api_level) is used as a
statement for 'if' to guard the API callers. For example:

if API_LEVEL_AT_LEAST(__ANDROID_API_V__, 202404) {
  new_api_for_V_and_202404();
} else {
  fallback_function();
}

Bug: 302113279
Test: build trunk-staging and next configurations
Change-Id: I60d40655b1f8afdfa5c69b2ac4be2205f8057bea