make discord-bot and netlify-functions-ecommerce work with tables

[vkarpov15]

General idea:

1. Disable _id and __v because of underscore property names issue
2. Use insertMany() to create new documents and Model.updateOne() to update existing, as opposed to using save() and create(), because those rely on _id
3. Use id instead of _id as unique identifier
4. Comment out any logic that uses deleteMany(), dropCollection(), createCollection()
5. Any nested properties are stored as JSON strings

Outstanding questions:

1. Any workaround for lack of deleteOne() and deleteMany()? Hard to write tests without those.

[vkarpov15]

Current outstanding issues:

1. addIndex not handling camelCased names (addIndex seems to fail on names with uppercase (missing double quotes)? data-api#1404)
2. $in support for Mongoose populate (Add support for $in for API Tables  data-api#1415)
3. Sorting in find()
4. skip

[vkarpov15]

In ae819af, I showed that Mongoose studio's basic functionality of displaying documents works with tables as well.

The missing features are:

5. estimatedDocumentCount()
6. countDocuments()

I worked around this limitation using the following code:

  const numDocuments =
    await Model.find(filter).then(docs => docs.length);