Motivation

In order to complete SERVER-91195, we should provide a backportable solution taking into account that collection cloning procedures are always:

1. Calling into listCollections.
2. Extracting the options and indexes fields from the listCollections output.
3. Creating collections in the catalog with such options/indexes.

It follows that any catalog parameter should be somehow included in the metadata as part of the options or indexes sub-objects. The options object is the most suitable for hosting collection properties, but we must take into account the following limitations: 

       A. Collection options are strict (can't add new top-level fields to the options object).

       B. Time-series options are strict (can't new top-level fields in the options.timeseries sub-object).

Due to (A) and (B) the only viable way to include some collection option in older [sub-]versions without breaking parsing and backwards compatibility would be adding this information to some of the existing collection options sub-objects.

The storageEngine sub-object is the only suitable parameter because it's the only one that can be modified without breaking parsing: it can contain an app_metadata field supposed to host metadata useful for WT users (such as the mongodb catalog) and totally ignored by the storage engine.

Objective

Purpose of this ticket is to provide a simple set of abstractions to manipulate storage engine config strings (passed as BSON or as std::string):

• Get a flag from a storage engine config string
• Set (add/edit) a flag on a storage engine config string

Given the current use cases, at moment we only need to provide support for boolean flags.