Support for nested profiles

Sort of continuation to #47.

My understanding is that right now optional default values go into .oci/oci_cli_rc while high-level profile settings (user, tenancy, fingerprint, key_file, region) go into .oci/config.

While it would be easier if all settings lived under one roof, with the current layout of two separate config files, would there be an easy way to support nested profiles?

For example, let's say that I have a tenancy T with 2 compartments A and B. Right now, I need to create 2 identical profiles in .oci/config for the auth settings, and then 2 profiles in .oci/oci_cli_rc with the corresponding compartment-id.

Ideally, I would want to have the auth settings defined within [T] in .oci/config, which also defines two child profiles [A] and [B] (let's say with a new import keyword referencing the T profile). Alternatively, instead of nested profiles it would be nice if multiple profiles could be created with the same settings in .oci/config (e.g. [A] [B])

Would any of these approaches be possible to implement?

The issue points to .oci/config and .oci/oci_cli_rc; start by tracing how profiles and optional defaults are loaded. Compare nested/import profiles with sharing settings across multiple profiles. Done means a decided approach lets child profiles reuse authentication settings while selecting distinct compartment IDs.