chore(5-min-viz): organize streamlit app

place app_stations.py under districts to match pems_web and
to use the more accurate streamlit app name "districts--stations"

Author: lalver1

pems_streamlit/src/pems_streamlit/apps/stations/__init__.py renamed to pems_streamlit/src/pems_streamlit/apps/districts/__init__.py

@@ -9,7 +9,7 @@
         <div class="col-lg-12">
             <iframe title="District {{ current_district.number }} visualization"
                     class="w-100 h-100"
-                    src="{{ streamlit.url }}/stations--stations?embed=true&district_number={{ current_district.number }}">
+                    src="{{ streamlit.url }}/districts--stations?embed=true&district_number={{ current_district.number }}">
             </iframe>
         </div>
     </div>

pems_streamlit/src/pems_streamlit/apps/stations/app_stations.py renamed to pems_streamlit/src/pems_streamlit/apps/districts/app_stations.py

@@ -16,7 +16,7 @@
                 {% block districts-content %}
                     <div class="row" style="min-height: 450px;">
                         <div class="col-lg-12">
-                            <iframe title="District visualizations" class="w-100 h-100" src="{{ streamlit.url }}/stations--stations?embed=true">
+                            <iframe title="District visualizations" class="w-100 h-100" src="{{ streamlit.url }}/districts--stations?embed=true">
                             </iframe>
                         </div>
                     </div>