[core] Validate that zowe.config.json file matches schema

[t1m0thyj]

Given a zowe.config.json file that references a zowe.schema.json file, validate that the contents of the JSON file conform to the schema.

[t1m0thyj]

In #116 a new method was added to validate config files against a JSON schema. There are some further enhancements to make:

• Automatically detect schema filename from $schema property in the config file - can be a file path or Internet URL
• Move the validation logic into the ProfileManager class as opt-in behavior to auto-validate when profiles are loaded

[Aman123lug]

Hello Sir, I am Applying for Zowe Python SDK Enhancements for this project. Is any number of PRs required in order to become a mentee

[t1m0thyj]

• Missing $schema property - warning?
• Invalid $schema property - error?
• Valid $schema property - throw errors for any validation fails
• Have flag to disable schema validation