Add configuration import

Problem/Motivation

As a user of this module it would be nice if the configuration for the alert type was created by enabling this module.
As an existing user of the Sitewide Alert module, it would be nice if enabling this module did not blow out any existing types that we had previously defined.

Acceptance Criteria

1. Types of USWDS Alert showed in the Sitewide Alert "Type" selector.
1. Alert - Success
2. Alert - Warning
3. Alert - Error
4. Alert - Informative
5. Alert - Emergency
6. Alert information paragraph width, and Slim should not be added because the narrow version would not be used in the blocks, they are more for use within content.
2. Types of USWDS Site Alert showed in the Sitewide Alert "Type" selector.
1. Site Alert - Informational
2. Site Alert - Emergency
3. Enabling this module should not overwrite any pre-existing "Types" if the Sitewide Alert module is already in use.

Proposed resolution

There are three options that occur to me at this time:

1. Add config/install yml that is a copy of what you get when you create these by hand then to config export. Thre drawback to this method is that it will overwrite existing Types.
2. Create a Recipe. - it is not clear if a recipe can add to existing config or if it always overwrites.
3. Create a hook_install that adds them programatically.