src: refactor profile initialization

- Process and store --cpu-prof-dir and --cpu-prof-name during
  Environment creation
- Start profilers in one `profiler::StartProfilers()`

PR-URL: https://github.com/nodejs/node/pull/27475
Refs: https://github.com/nodejs/node/issues/27421


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>