Add options for ConfigFactory to handle customConfig properly

[mkondratek]

Fixes https://linear.app/sourcegraph/issue/CODY-4264/a-comment-in-cody-settingsjson-breaks-cody-initialization-stuck-at.

Test plan

1. Have the cody_settings.json like this:

{
  // other providers...
  "openctx.providers": {
    "https://gist.githubusercontent.com/thenamankumar/3708f084fb2abd57adafe7f14620bdf7/raw/e7c7059cb5b04f6feead002e7b3a90c5b1a4bb96/provider.js": true
  }
}

2. Cody should initialize

[mkondratek]

ConfigFactory does not render json. The rendered config contained the comment with # instead of //. Using JsonParser fixes the problem.

[pkukielka]

Other option would be adding .setComments(false) in the current code.
I thought Lightened Config was a bit more forgiving when parsing e.g. additional commas.
Maybe we can write simple test for that and check how those corner cases looks in case of both approaches?

[mkondratek]

fixed

[mkondratek]

There was a bug 😄 configs are immutable

[mkondratek]

Basically, we ignored "foldingRanges": "indentation-based" - how important for us is this option?

[mkondratek]

withValue adds the field as

"cody": {
  "experimental": {
    "foldingRanges": "indentation-based"
  }
}

instead of

"cody.experimental.foldingRanges": "indentation-based"

Is it a problem? 🤔

[pkukielka]

IMHO It is not, those are equivalent in VSC config.

[pkukielka]

LGTM