Support nested team config files

[t1m0thyj]

Currently only top-level profiles get loaded. We should support a zosmf child profile with a typeless parent profile like the following:

{
    "$schema": "./zowe.schema.json",
    "profiles": {
        "lpar1": {
            "profiles": {
                "zosmf": {
                    "type": "zosmf",
                    "properties": {
                        "port": 443
                    },
                    "secure": []
                }
            },
            "properties": {
                "host": "example.com",
                "rejectUnauthorized": true
            },
            "secure": [
                "user",
                "password"
            ]
        }
    },
    "defaults": {
        "zosmf": "lpar1.zosmf"
    },
    "autoStore": true
}

[t1m0thyj]

Currently, we support loading "flat level" profiles like the following:

{
    "$schema": "./zowe.schema.json",
    "profiles": {
        "lpar1_zosmf": {
            "properties": {
                "host": "example.com",
                "port": 443,
                "rejectUnauthorized": true
            },
            "secure": [
                "user",
                "password"
            ]
        }
    },
    "defaults": {
        "zosmf": "lpar1_zosmf"
    },
    "autoStore": true
}

from zowe.core_for_zowe_sdk import ProfileManager
profile_manager = ProfileManager(show_warnings=False)
print(profile_manager.load(profile_type="lpar1_zosmf"))

This will print the host, port, and rejectUnauthorized properties for the "lpar1_zosmf" profile.

The example config JSON at the top of the page uses nested profiles to store properties separately at the top level ("lpar1") and in a sub-profile ("lpar1.zosmf").
We want to support the following:

from zowe.core_for_zowe_sdk import ProfileManager
profile_manager = ProfileManager(show_warnings=False)
print(profile_manager.load(profile_type="lpar1.zosmf"))  # Note the "." indicating a nested profile

Currently this fails. Instead we want it to load host and rejectUnauthorized from the "lpar1" profile, and port from the "lpar1.zosmf" profile, and print them all.