src: add tracing category macros

Adds `TRACING_CATEGORY_NODE`, `TRACING_CATEGORY_NODE1` and
`TRACING_CATEGORY_NODE2` helper macros for consistently building
trace event category strings. For instance,

`TRACING_CATEGORY_NODE2(foo, bar)` would generate the category
string `node,node.foo,node.foo.bar`, such that...

```
TRACE_EVENT_NESTABLE_ASYNC_BEGIN0(
    TRACING_CATEGORY_NODE2(foo, bar),
    "baz", 1);
```

Would emit if trace events are enabled for categories: `node`,
`node.foo`, or `node.foo.bar`.

This allows a natural scoping down of what trace events a user
may want to receive. Enabling the `node` category would receive
everything Node.js produces.

PR-URL: https://github.com/nodejs/node/pull/19155


Reviewed-By: Andreas Madsen <amwebdk@gmail.com>