Add doc for the footer, fix link to folder structure in web app overview page,...

Add doc for the footer, fix link to folder structure in web app overview page, add uderline on '<a>' tags present in the main content of the documentation

docs/components/custom-apps/web-app/footer.md

+# Footer
+
+The footer is devided in three sections.
+
+The left section comports links to the facebook and twitter pages of the Lyon Metropolis as well as the link to the RSS feed of the platform.
+
+The middle section is composed of internal links to different pages of the web app. Besides it also has a `Download the catalog` link which triggers the download of a CSV export of the metadata catalog through the [CSV catalog downloader](../../services/csv-catalog-downloader.md) service.
+
+The right section only has a link to the official [website](https://grandlyon.com) of the *Grand Lyon*.

docs/components/custom-apps/web-app/overview.md

@@ -6,7 +6,7 @@ Organize a folders and files structure inside a project is never an easy task, a
 We think that at the beginning we should just not overthink about it, choose one way to do it, keep to it, until a natural re-organization will happen if needed.   
 Here is our `/src` folder structure:
 
-![folders structure](../../assets/web-app-project-structure.png)
+![folders structure](../../../assets/web-app-project-structure.png)
 
 * `src/app/`: where the Angular code is located. With time we organized this part in different modules each taking care of one main functionnality. Here is the list of the modules:
   * `core/`: constitutes the base of the application (layout, notifications, navigation history...)

docs/extra.css

@@ -6,4 +6,8 @@ body {
   background: white;
   border: 1px solid #dcd9d9;
   margin-bottom: 2rem;
+}
+
+.md-content a {
+  text-decoration: underline;
 }
\ No newline at end of file

mkdocs.yml

@@ -43,7 +43,7 @@ nav:
           - Dataset:
             - Data: components/custom-apps/web-app/dataset/data.md
             - Information: components/custom-apps/web-app/dataset/info.md
-            - API \& Downloads: components/custom-apps/web-app/dataset/resources.md
+            - API & Downloads: components/custom-apps/web-app/dataset/resources.md
           - Header: components/custom-apps/web-app/header.md
           - Footer: components/custom-apps/web-app/footer.md
           - Drafts: components/custom-apps/web-app/drafts.md