Move from submodules to secondary package.json

[leoj3n]

Submodules were a good way to get things organized for the first wave of sweeping changes but won't work so well for collaboration (most people don't know submodules) and, as it turns out, it's not possible to publish to npm from a git submodule:

canjs/canjs#3575

Therefore we will move to having a second package.json and a nested node_modules directory that will be used to store all the modules to be documented. This will be located at:

docs/modules/package.json

There will also be a .gitignore in that directory:

docs/modules/.gitignore

This will ignore the nested node_modules in that directory:

docs/modules/node_modules

In the main package.json, the bit-docs config will be updated from:

    "glob": {
      "pattern": "docs/**/*.{js,md,mustache,less}",
      "ignore": [
        "**/node_modules/**/*"
      ],
      "follow": true
    }

To:

    "glob": {
      "pattern": "docs/**/bit-docs*/*.{js,md,mustache,less}",
      "ignore": [
        "docs/modules/node_modules/**/node_modules/**/*"
      ],
      "follow": true
    }