[Exports] Add exports configuration to YAML spec

[courtneyholcomb]

Housekeeping

• I am a maintainer of dbt-semantic-interfaces

Short description

Add exports options to YAML spec.

Acceptance criteria

YAML for exports should look like the following (nested under saved_queries):

saved_queries:
  - name: my_query
    description:
    query:
      metrics:
        -
      group_bys:
        - TimeDimension()
        - ...
      where:
        -
    exports:
      - name: my_query 
         config:
           export_as: table # options: table, view - FUTURE: incremental_table, window_table, file
           schema: my_schema  # [optional - DEFAULT to deployment schema]
           alias: some_table_name # [optional - DEFAULT to export name]

Impact to Other Teams

N/A

Will backports be required?

No

Context

No response

[Jstein77]

cc @QMalcolm