Make ui_next the default UI (#15405)

Change django url dispatcher to serve up ui_next files instead of old ui files

Old UI will not be served with this change

Github CI still runs old ui tests (to be removed in another PR)

Remove the Github workflows that build old UI

---------

Signed-off-by: Seth Foster <fosterbseth@gmail.com>

.github/actions/run_awx_devel/action.yml

@@ -57,16 +57,6 @@ runs:
           awx-manage update_password --username=admin --password=password
         EOSH
 
-    - name: Build UI
-      # This must be a string comparison in composite actions:
-      # https://github.com/actions/runner/issues/2238
-      if: ${{ inputs.build-ui == 'true' }}
-      shell: bash
-      run: |
-        docker exec -i tools_awx_1 sh <<-EOSH
-          make ui-devel
-        EOSH
-
     - name: Get instance data
       id: data
       shell: bash