Add CLI override support for settings and schema

[dshore]

Description

Allow advanced users to easily override settings and schema configuration files which will allow for things like this:

• Custom currencies
• Custom bidder codes

Acceptance Criteria

Add the following CLI options:

• --settings (this will replace the default settings file)
• --schema (this will replace the default schema file)
• show settings (allows for easily copying the default)
• show schema (allows for easily copying the default)