[WIP] src: introduce node_bootstrap and node_process

Furthering the cause of breaking node.cc up into smaller, more manageable chunks.

This does two main things:

1. Adds a new bootstrapper object that is used only during bootstrap to avoid having to delete and overwrite properties on process during bootstrap

2. Moves most of the process function and property definitions to node_process.cc for better isolation.

Functionality is the same, tho there are some code cleanups along the way. This should be semver-patch.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines