PDI-1454: CLI v2 Command: Custom Request

[erikostien-pingidentity]

• Add Command Usage examples and Configuration format examples to cobra usage messages where applicable.
• Unite all Pingone and Pingfederate configuration options under 'service' parent, now used by both 'platform export' and 'request' commands.
• Add 'authentication' parent in service configuration to allow the user to directly specify which authentication method to use. This removes the flag exclusivity requirement on 'platform export' command, as well as removes authentication "heirarchy" in pingfederate go-client authentication logic.
• Refactor MultiService custom map type to ExportServices []string type.
• Add new command 'request' to send custom request to PingIdentity services. Currently, only PingOne is supported.
• Add multiple additional custom types to support Ints, authentication types, http methods, and request services.
• In the configuration file, support Yaml array lists for scopes, CA cert files, and Export services.
• Use PingOne region codes instead of deprecated PingOne Regions.
• Various testing fixes and additions.