process: run RunBootstrapping in CreateEnvironment

Also creates `CreateMainEnvironment` to encapsulate the code
creating the main environment from the provided Isolate data
and arguments.

PR-URL: https://github.com/nodejs/node/pull/26788


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Refael Ackermann <refack@gmail.com>